Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. You learned what they are and how to use them. Tweet a thanks, Learn to code for free. How can I pass image url from parent component to child component via props [REACT.JS], "WebExtension::executeScript: content script injected VM149:1" in Chrome loading React app. More on that next! In this case Id rather avoid duplicating images (with the potential that the copies get out of sync). Often, it indicates that you should split your components and pass children as JSX. The same one youd use in HTML. We also have thousands of freeCodeCamp study groups around the world. Some of our partners may process your data as a part of their legitimate business interest without asking for consent. Is quantile regression a maximum likelihood method? Is lock-free synchronization always superior to synchronization using locks? However when I try to abstract the data into a JSON file and import it into the App.js file, I am stumped on the best . One of the main ways developers can achieve this functionality is by using props. You may also go to Stackblitz for the demo: React Wave Effect Tutorial. You cant change props. Its old props will then be cast aside, and eventually the JavaScript engine will reclaim the memory taken by them. Here we have three wave components that have varying duration, direction, and opacity to create the awesome wave effect. There is an icon with each exercise mode. in. No, its actually common practice to destructure the props before using them, so relax , Youre welcome Kirti. Create another file called AdditionalDescription and pass in some props in the form of a name and description in its function: We'll then have two paragraph tags showing the name and description. While we want to reuse the component, we also want to update the name of the product, the price, the description, and the image without having to hard code any data in the Product.js component. This article talked about everything you need to know about props as a beginner. Youll need to choose what props to pass to it. This article will explain what props are and we'll look at the syntax for passing and receiving props. How to pass a function as a prop to React function component? Add a "brand" attribute to the Car element: const myElement = <Car brand="Ford" />; The component receives the argument as a props object . You can think of props like knobs that you can adjust. This lets you use them inside the Avatar code, like you would with a variable. React UUID Component Generator Example | React Native UUID example, Basic React Interview questions and answers, Best ways to add an element to an array in React state with examples, Difference between Development and Production Builds in React, Difference between pureComponent and component in React. What would happen if an airplane climbed beyond its preset cruise altitude that the pilot set in the pressurization system? Option 1: import the image into the component. The open-source game engine youve been waiting for: Godot (Ep. How to register conversion to Google Adwords in ReactJS with react-ga? 542), We've added a "Necessary cookies only" option to the cookie consent popup. 3.3. props gets passed as a parameter to our functional component. Then we'll take a look at how to use props with destructuring. Its a separate, optional npm package, so you need to install it first before using it: Now lets make required props in theGreetingcomponent: With thepropTypesproperty declared, theGreetingcomponent will throw a warning to the console when its props arent passingpropTypesvalidation. and take any name as a prop in the tag and then pass it!! Sometimes ( Mostly ) I do this inside child components before the return fucntion. Copyright Cloudhadoop.com 2023. Below is what we'll be making today, the waves are smooth and it's not random like react-wavify. First, let's create a new NextJS project by running the command: Once the installation is complete, you can run the following command to start the local server: Next, let's create the AnimatedWave component by creating the file components/AnimatedWave.tsx, and copying the code below. This means that data can only be transferred from the parent component to the child components. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. We accomplish this by creating thousands of videos, articles, and interactive coding lessons - all freely available to the public. My advice? There was an error submitting your subscription. Then our rendered components consume those properties and pass data into them. Find centralized, trusted content and collaborate around the technologies you use most. First, pass some props to Avatar. How can I recognize one? A common mistake for beginners is to set the src to a file path on their computer, like /Users/yourname/Projects/this-react-app/src/image.png. However, props are immutablea term from computer science meaning unchangeable. So if you had an image at public/images/thing.jpg, you could display that image this way: Because this method makes the image available as a regular file on the web server, and you can test it by opening http://localhost:3000/images/logo.jpg in the browser (or, you know, your actual domain name, once its deployed! This Gallery component contains some very similar markup for two profiles. Teams. We can also refer to it as ancestor to descendant, or parent to child. You can put the image file in the public folder (or if this is not Create React App then any folder that will be copied to the server). I think this code can be improved so that we don't rely on hard-coded height, backgroundSize, and background-position. Connect with me on Twitter @JoyPaces. You use props to pass data and values from one component to another to get dynamic and unique outputs. Making statements based on opinion; back them up with references or personal experience. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Since props can be passed from top to bottom, we can create another child component in which we can pass down the parent's attributes. Let's now look at how to pass in props with destructuring. There are a couple of tricks that you can use to improve the code quality of your application. Let's build and connect the components that we will be working with in this tutorial together. This is how props enable you to send data using the top-down approach, wherein a component at a higher level can send data to a component below it. How do I pass command line arguments to a Node.js program? Sci fi book about a character with an implant/enhanced capabilities who was hired to assassinate a member of elite society, The number of distinct words in a sentence. The defaultProps is a React component property that allows us to set default values for the props argument. Props are directly accessible in a component, even though declaring a constructor. The answer is its not possibleat least not directly. In React applications, Images are served from different folder locations. I would expect to see something like this where you want to use games: Thank you for reaching out @Sky020 and pointing this out, Ill fix it. As you develop your React application, sometimes you might need a prop to be structured and defined to avoid bugs and errors. It works without a constructor. Adding images in the public folder and the src folder both are acceptable methods, however, importing images into your component has the benefit that your assets will be handled by the build. The Complete React Native + Hooks Course [2019 Edition] Building Reusable Components For example, className, src, alt, width, and height are some of the props you can pass to an : The props you can pass to an tag are predefined (ReactDOM conforms to the HTML standard). Learn more about default props in React here. Typescript and Google AMP? I have two type props. Here's a table below to show how they differ: They allow you to pass data from one component to another, They hold information about the components, They can be passed down and accessed by a child component, They cannot be accessed by a child component, Props are basically used to communicate between components, State is used for rendering dynamic changes. You can directly provide the path in App.js while calling componentif(typeof ez_ad_units!='undefined'){ez_ad_units.push([[336,280],'cloudhadoop_com-large-leaderboard-2','ezslot_10',124,'0','0'])};__ez_fad_position('div-gpt-ad-cloudhadoop_com-large-leaderboard-2-0'); if images are in the src folder, you have to import the image with a path from using the import feature, Call the above component created with passing url=myimage, You learned how to load images from URL/local public/src folder and display them in Reactjs applications. And the second by passing a callback, we can take the default props . Simple React Scroll Animations With Zero Dependencies. How to pass an object as a prop in React using typescript? Other than quotes and umlaut, does " mean anything special? The last example for passing data actually represents another common problem you might encounter when dealing with props and state: prop drilling. Dave Ceddias Pure React is a work of enormous clarity and depth. I have an image uri that i want to pass as prop so that i can load it when it when the component is rendered. This alone will not automatically make it available, so you have to import the image into the React component where you're using it. I created new reactjs application, now I got data from API and displayed table but I need edit row next page. Destructuring is a JavaScript feature that allows you to extract sections of data from an array or object. This demonstrates that you can pass any type of data available in JavaScriptsuch asnumber,Boolean, orobjectinto props. Every parent component can pass some information to its child components by giving them props. Like this article? Thanks for contributing an answer to Stack Overflow! Now let's relate the syntax above to our App.js: The live output of the code above now displays image, name, and description peculiar to each product. In App.js, multiple images are passed as a property to a component. (The parent components code is omitted because it uses state, which we wont dive into just yet.). try LogRocket today. You can read these props by listing their names person, size separated by the commas inside ({ and }) directly after function Avatar. Lets first return to the code example withstate: Its very common for a React application to have as many as three component layers, with the top-layer component calling on a child component that calls on another child component. How to pass id in path url as component property in react router v6, How to pass an array in query parameter url react. Try tweaking the values! I am not sure what Im doing wrong. A parent component is any component that calls other components in its code block, while a child component is simply a component that gets called by a parent component. It is common to nest built-in browser tags: Sometimes youll want to nest your own components the same way: When you nest content inside a JSX tag, the parent component will receive that content in a prop called children. Yes, possible to load multiple images with the single component declaration. You define image as a required prop, but you are the destructuring image from the property prop instead of the image prop. I respect your email privacy. React component functions accept a single argument, a props object: Usually you dont need the whole props object itself, so you destructure it into individual props. You can make a mistake and forget to pass a required prop into the component that needs it: Whileprops.ageandprops.occupationare undefined in theGreetingcomponent, React will simply ignore the expression to call on their value and render the rest of the text. But you can pass any props to your own components, such as , to customize them. Then you can either store it into a variable called props within the body of the function or pass it directly as the function's parameter. On theChangeGreetingcomponent, it will call on thehandleClickfunction when the button is clicked, causingAppto execute the function. How do I remove a property from a JavaScript object? Fix for Error No configuration provided for scss, Multiple ways to List containers in a Docker with examples, What is the difference between Promise race and any methods with examples, What is the difference between Promise all and allSettled methods with examples. Then, assuming your server is treating the public folder as the root directory (/), then your images will be available relative to that just like with plain HTML. When you need interactivity, youll need to set state. Props are handy! Programmatically navigate using React router. rev2023.3.1.43266. No Spam. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Props are objects. How is that relevant to the question? 542), We've added a "Necessary cookies only" option to the cookie consent popup. Second, So you need to create multiple components for displaying multiple images.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[728,90],'cloudhadoop_com-box-4','ezslot_2',121,'0','0'])};__ez_fad_position('div-gpt-ad-cloudhadoop_com-box-4-0'); You might ask: how do you handle multiple images? It has worked for me and hope this will help others. show, They serve the same role as arguments serve for functionsin fact, props are the only argument to your component! article, If you import image as if you were importing a package, you won't have to move your images into public folder, I think. Note that the two ways of destructuring that I demonstrated above will always have the same output. Try changing the color in the select box below: This example illustrates that a component may receive different props over time. Passing props in React: conclusion. Image recognition objective I've added to my location-based RN game. How props are passed into a component is similar to how attributes work in HTML elements. But we haven't yet achieved our goal, right? The full code is accessible on GitHub: React Wave Effect. States and props together form the data model of a React application. How did Dominion legally obtain text messages from Fox News hosts? How to delete all UUID from fstab but not the UUID of boot filesystem, First letter in argument of "\affil" not being output if the first letter is "L". You can then assign the URL relative to your host address to set the background image. In The component, Move the setting of the URL to the outside component. To pass props to a class component you define the name of the prop and then pass a value inside curly brackets. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. In this tutorial, we'll learn to work around this limitation. Now that we've done that, we can go back to our App.js to render our product and pass some data to these three props. For example, you can change the person or the size props inside Profile without having to think about how Avatar uses them. Focus on the React bugs that matter TheGreetingcomponent didnt actually need it, but its child component,ChangeGreeting, does, so it forwards the prop there. When the state inAppis updated, React view is re-rendered, and the new state value is then sent toGreetingthrough props. Step 2: Read props inside the child component. Simon Holdorf. How to pass the React Router location prop to a component? if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'cloudhadoop_com-banner-1','ezslot_8',126,'0','0'])};__ez_fad_position('div-gpt-ad-cloudhadoop_com-banner-1-0');this way, It is very easy and simple to load images from URL in reactjs. or is it when the application is build/compile time? This topic was automatically closed 182 days after the last reply. Get started, freeCodeCamp is a donor-supported tax-exempt 501(c)(3) charity organization (United States Federal Tax Identification Number: 82-0779546). Hats off. Because they perform an essential function they pass data from one component to another. Do flight companies have to make it clear what visas you might need before selling you tickets? If you read this far, tweet to the author to show them you care. how to retrieve usdt from metamask; adductor muscles action; bank of america mlb sponsorship In order to do that, you need to usestate. Ackermann Function without Recursion or Stack, Is email scraping still a thing for spammers. For that reason, I lean toward importing an image if Im going to use it. At some point, you may start noticing that the process is quite inefficient overall. Leverage this knowledge to build cool stuff! Props are read-only. Was Galileo expecting to see so many stars? Let me show you how I greet myself: This is the very basis of props: it allows you to send any data you can think of into a component when you call on that component. Our mission: to help people learn to code for free. Here's an example: The image path is ./cube relative to Parent which means it resides in the same directory as Parent. If you read this far, tweet to the author to show them you care. To pass props, add them to the JSX, just like you would with HTML attributes. Get up-to-date on latest articles on react.js, node.js, graphql, full-stack web development. and take any name as a prop in the tag and then pass it!! Also, avoid using string literals in refs. Once the installation is complete, you can run the following command to start the local server: cd react-wave-effect yarn dev. I would like to create a "card style" list of workouts. A state can change over time, and this change can happen as a response to a user action or a system event. Please share this article if you found it helpful. How to pass props in the modal in react Path isn't changing using Router instead of BrowserRouter ReactJS: Maximum update depth exceeded with localstorage How to Use Classes in Styled-Component React router always showing NotFound component Is there a way for some grid items to start from left and some for the right in same line? How to draw a truncated hexagonal tiling? So for example: Context lets you create a component (a Provider) that has one prop (value) that you store some values in. i wanted the image to display which im getting from the url of json object which is image.url in slides.vue as props . There are 3 ways of passing props through Link through url parameters: <Link to="/daggala"> through state: <Link to={{pathname:"/", state: {fromDashboard: true }}}> not through state: <Link to={{pathname:"/", fromDashboard: true }}> I'll assume that you're using hooks and v5 or v6 of react router. We already completed the component but, we haven't defined the keyframes for the animation, let's add that in globals.css. State can only be accessed or modified inside the component. Hello, in this tutorial, you'll learn how to create a react wave animation using an SVG element and some CSS. Props take the place of class attributes and allow you to create consistent interfaces across the component hierarchy. It accepts props, and those props match one of the context items, but you havent shown how youre rendering that collection of items. That wont work. I wanted to try creating a wave animation background in react. either type props originate from data.js objects properties(image) and other type I add separately(text,switch). So we can't successfully work with props without having a component to work with. We first had to initialize it, and we then needed to access the props and what kind of property it holds. If the image is especially small, Webpack might even decide to inline it into the JS bundle, as an optimization. Helpful articles to improve your skills. Instead, it makes a note that this particular JS file depends on this particular image/CSS file/whatever. For example. Glad you find it useful. Props are directly accessible in a component, even though declaring a constructor. We accomplish this by creating thousands of videos, articles, and interactive coding lessons - all freely available to the public. You can find me online at, to optimize your application's performance, Jest and Enzyme: Unit testing in React in 2021, How to make an idle timer for your React. onClick ), First, know that imports are not handled by React at all theyre handled by your bundler, which is probably Webpack. Then you can either store it into a variable called props within the body of the function or pass it directly as the functions parameter. But heres the thing in React: you can also pass afunctionas props. Tweet a thanks, Learn to code for free. First, it uses a png file for the wave, meaning you can't easily change the background color of the waves unless you change the png file. Acceleration without force in rotational motion? Props stands for properties, and they are used in a React application to send data from one React component to another React component. The props enable the component to access customised data, values, and pieces of information that the inputs hold. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. as i will be changing images i cannot have a static uri. Full access to all its features - serverless, streamed responses, keep track of conversations, etc. } = props; I do to save myself writing this.props before every variable. Please try again. freeCodeCamp's open source curriculum has helped more than 40,000 people get jobs as developers. We'll also use NextJS as our react framework as a personal preference of mine, but you can also use create-react-app or other alternatives. To learn more, see our tips on writing great answers. How does a fan in a turbofan engine suck air in? (And no, the solution is not to put it in the same place on the server :). Sometimes, passing props gets very repetitive: Theres nothing wrong with repetitive codeit can be more legible. Difference between super and super props in React constructor class? But since props are read-only and must not be changed manually throughout the lifespan of a React application, using only props in your React app doesnt really make it a dynamic app that can respond to user interactions and render accordingly. When you have many components, and all of them are interacting with each other using props and state, prop drilling can become a headache to maintain. How do I include a JavaScript file in another JavaScript file? To reuse the 'Product.js' component to show the data of other products, all we need to do is to attach the new data or values when re-rendering the component. Why do we kill some animals but not others? Thank you for your honest feedback, I will give it a try hopefully it works. Because we seem to be missing some code here. There are 2 main ways to do that. You can think of a component with a children prop as having a hole that can be filled in by its parent components with arbitrary JSX. I'm a React trainer in London and would thoroughly recommend this to all front end devs wanting to upskill or consolidate. Then, I attached the values of the props alongside them. Why does the Angel of the Lord say: you have not withheld your son from me in Genesis? When we structure the App.js component properly, it will now look like this: There's a slight difference between writing HTML attributes and passing in props: while HTML attributes are special keywords already provided for you, you customize and define props in React. Making statements based on opinion; back them up with references or personal experience. Because they dont use any of their props directly, it can make sense to use a more concise spread syntax: This forwards all of Profiles props to the Avatar without listing each of their names. A function component will receive thepropsobject with properties you described in the component call: Aside from passing multiple props at once, in this example, you also see theageprop is a number data type. Donations to freeCodeCamp go toward our education initiatives, and help pay for servers, services, and staff. Props take the place of class attributes and allow you to create consistent interfaces across the component hierarchy. How do I change the font color of an option only once it's been selected from a select drop down menu? How do I conditionally add attributes to React components? The first thing to note is while props are read-only and are immutable, while states change asynchronously and is mutable. The concept of props is built on the concept of components. Now let's use the syntax above to pass data into the App.js component: In the code above, the component name within the tag is Product, and the first property or prop is img with its value https://m.media amazon.com/images/W/WEBP_402378T1/images/I/71TR1WrqqJL.AC_UL320.jpg attached to it. Put the image file somewhere under the src folder. But I need edit row next page state inAppis updated, React is! Back them up with references or personal experience and help pay for servers, services and! Data as a prop in the tag and then pass it! inside Avatar! And would thoroughly recommend this to all front end devs wanting to upskill or consolidate to... Article will explain what props are immutablea term from computer science meaning unchangeable know about props as a.... Conditionally add attributes to React components thing for spammers and interactive how to pass image url as props in react lessons all. Our goal, right are served from different folder locations the parent components code omitted. Are read-only and are immutable, while states change asynchronously and is mutable the. I would like to create consistent interfaces across the component but, 'll. Is image.url in slides.vue as props back them up with references or personal experience you define the name of prop. Is re-rendered, and staff I conditionally add attributes to React components the component. Allows you to how to pass image url as props in react sections of data available in JavaScriptsuch asnumber, Boolean, orobjectinto props duration. Us to set default values for the props before using them, so relax, welcome! Them, so relax, Youre welcome Kirti as < Avatar >, to customize them without. Which we wont dive into just yet. ) into a component beginners is set. Asynchronously and is mutable today, the solution is not to put it in the and. Props argument to show them you care pay for servers, services, and this change can happen as prop! Do this inside child components by giving them props a response how to pass image url as props in react a file path their. Of destructuring that I demonstrated above will always have the same place on the concept of is! Wrong with repetitive codeit can be improved so that we do n't on. Inefficient overall ancestor to descendant, or parent to child browse other questions,! Inside the Avatar code, like you would with a variable tricks that you can use improve! To Stackblitz for the props alongside them is while props are read-only and are immutable while., privacy policy and cookie policy the open-source game engine youve been waiting for: Godot (.. You have not withheld your son from me in Genesis to it another React component to work props... Computer science meaning unchangeable particular JS file depends on this particular image/CSS file/whatever initiatives! Cast aside, and staff Dominion legally obtain text messages from Fox News hosts elements! Possible to load multiple images how to pass image url as props in react the potential that the copies get of. Change over time, and staff as props etc. passing props gets passed as prop! On their computer, like you would with a variable multiple images passed... Html elements a static uri ; ve added to my location-based RN game separately ( text, switch.. Over time, and staff attributes to React function component is email scraping still a thing for.. With references or personal experience them, so relax, Youre welcome.... Is what we 'll be making today, the solution is not to put it in the and. Article if you read this far, tweet to the cookie consent popup a component... Helped more than 40,000 people get jobs as developers has helped more than people... Completed the component hierarchy the only argument to your component we 'll look at how to pass to as. Education initiatives, and opacity to create a React application to send data from API displayed. The pilot set in the same output on hard-coded height, backgroundSize, interactive! Full code is omitted because it uses state, which we wont dive into yet. Props without having to think about how Avatar uses them, in this tutorial together response to a path! That have varying duration, direction, and the new state value is then sent toGreetingthrough props are term. Same place on the concept of props like knobs that you can then the... Put the image is especially small, Webpack might even decide to inline it into the component hierarchy orobjectinto.. And unique outputs work in HTML elements note that this particular JS file depends on this particular JS file on! Personal experience React application direction, and pieces of information that the how to pass image url as props in react hold be making today, waves. We have n't defined the keyframes for the demo: React wave.! Then assign the URL relative to your host address to set the src to a component similar! On writing great answers happen if an airplane climbed beyond its preset cruise altitude the. For two profiles first thing to note is while props are and how to conversion... Are a couple of tricks that you should split your components and pass children as JSX we. Very repetitive: Theres nothing wrong with repetitive codeit can be more legible for passing data actually represents another problem! Before the return fucntion decide to inline it into the component hierarchy Reach &... Duplicating images ( with the potential that the inputs hold receiving props split your components pass. For functionsin fact, props are directly accessible in a turbofan engine suck air in set background. To a component is similar to how attributes work in HTML elements graphql, full-stack web development to send from. It makes a note that this particular image/CSS file/whatever setting of the prop and then pass a value curly! To start the local server: ) bundle, as an optimization Effect tutorial Post your answer, you change. Heres the thing in React constructor class dive into just yet. ) then to! The setting of the Lord say: you have not withheld your son from me in?. Before using them, so relax, Youre welcome Kirti is re-rendered, we! Second by passing a callback, we 'll look at how to pass in with. There are a couple of tricks that you can pass any type of data one! Prop instead of the image to display which Im getting from the parent components is... On react.js, Node.js, graphql, full-stack web development particular image/CSS file/whatever is lock-free always! Be accessed or modified inside the child component the installation is complete, you can run the following to! Text, switch ) the awesome wave Effect wrong with repetitive codeit can be improved so we! Is not to put it in the tag and then pass it! varying duration, direction, and coding...: to help people learn to work with role as arguments serve for functionsin fact, props passed..., articles, and opacity to create consistent interfaces across the component hierarchy is clicked, causingAppto execute the.... As developers & quot ; card style & quot ; list of workouts Im. Text messages from Fox News hosts default props following command to start the local:! Obtain text messages from Fox News hosts properties ( image ) and other type I add separately text. Object which is image.url in slides.vue as props by creating thousands of videos, articles, eventually! The defaultProps is a work of enormous clarity and depth refer to it as ancestor to descendant or! Can happen as a part of their legitimate business interest without asking for consent mean anything special London and thoroughly... It when the state inAppis updated, React view is re-rendered, and they are used in component! Objects properties ( image ) and other type I add separately ( text, )... Arguments serve for functionsin fact, props are immutablea term from computer science meaning unchangeable is because! Duplicating images ( with the potential that the copies get out of sync ) create awesome! Applications, images are passed into a component is similar to how attributes work in elements! Children as JSX the src to a component, even though declaring a constructor parameter to terms... App.Js, multiple images with the potential that the two ways of destructuring that I demonstrated above will have! I add separately ( text, how to pass image url as props in react ) as an optimization ReactJS with react-ga of the main developers... Need to set the background image to learn more, see our tips on writing great.... People get jobs as developers with destructuring you might need before selling you tickets props... Animation background in React: you have not withheld your son from me in Genesis pass it!... Yes, possible to load multiple images with the potential that the set! It, and we 'll learn to code for free one component to another take the props... How does a fan in a component create the awesome wave Effect is lock-free synchronization superior. Instead, it makes a note that this particular image/CSS file/whatever of URL. When you need to choose what props are read-only and are immutable, while states change and... To register conversion to Google Adwords in ReactJS with react-ga you would with variable... 'Ll be making today, the solution is not to put it in the select box below: this illustrates! Copies get out of sync ) also pass afunctionas props the React Router location prop to React components in with. Altitude that the process is quite inefficient overall 'll learn how to pass the React Router location prop a., as an optimization improve the code quality of your application serve for functionsin,. A try hopefully it works or parent to child clear what visas you encounter! Of class attributes and allow you to create the awesome wave Effect is to set default values the! Thanks, learn to work around this limitation Google Adwords in ReactJS with react-ga passing callback.