Tag Archives: RouteComponentProps

Capturing Url Parameters in ReactJS using Typescript

This sounds like it’s a very easy thing to do. There are a lot of resources out there on the web, however, I certainly did not find it straight-forward.

My use case here was very simple: the site had failed to do something, I had the reason, and I just wanted to display that to the user (maybe at some stage I’ll move the response into the body, but I thought this would be an easy option for now.

How

The first step is to bring RouteComponentProps into your React file:

import { RouteComponentProps } from 'react-router';

Your component should have a class signature similar to this:

export class AddSiteFailure extends Component<IProps, IState> {

If you’re interested in some common Typescript syntax differences for React, I recently posted on this very subject.

In the above class definition, we’re accepting IProps and IState. IProps needs to be amended slightly:

interface IProps extends RouteComponentProps<IMatchParams> {    
}

interface IState {
}

So, we’re inheriting from the RouteComponentProps that we imported earlier, and we’re telling it that the structure of the parameters will be defined in an interface called IMatchParams. We’ll need to define that:

interface IMatchParams {
    reason: string
}

Okay, so far, we have a standard props structure, but we’re now inheriting from this new RouteComponentProps, and we’re telling it that the URL parameters will be defined in the interface IMatchParams. So, why does IMatchParams have a string property called “reason”?

The answer to that lies in your App.js / App.tsx. This is the file that manages the routing of your app. In the Render method, your file should have an entry similar to this:

<Route path='/addSiteFailure' component={AddSiteFailure} />

So, you need to tell it that you’ll be accepting a parameter, and you need to give that parameter a name; for example:

<Route path='/addSiteFailure/:reason' component={AddSiteFailure} />

Now, when you navigate to the page, the additional Url parameter will be internally referred to as “reason”, which is how it maps to IMatchParams.reason.