componentWillMount causes React.StrictMode to error

As per https://reactjs.org/docs/strict-mode.html#identifying-unsafe-lifecycles, I believe the following code is causing React apps using React.StrictMode to error, saying that this should be converted to the safer componentDidMount:

react-measure/src/with-content-rect.js

Lines 31 to 34 in 350c5ce

    
           componentWillMount() { 
        
             this._resizeObserver = new ResizeObserver(this.measure) 
        
             this.animationFrameID = null; 
        
           }

I'm not familiar with this library, but it seems like these could perhaps live in a constructor function?

If you think I'm on the right track, I'm happy to try a PR.

Yup! These should work fine in a constructor method. If you'd like to create a PR, I can review it and get it released. Thank you for filing an issue and being willing to make a PR! 🙏

Actually, you should be able to just add these as properties on the class, even easier ✨.

Rock on. I'll see if I can get something up tonight

@souporserious are you sure the README is up to date for getting set up? Couple of things:

there seems to be a yarn.lock file but no package-lock.json, implying that I should use yarn and not npm to do dev

running yarn run dev gives a webpack error saying:

The CLI moved into a separate package: webpack-cli
Please install 'webpack-cli' in addition to webpack itself to use the CLI
-> When using npm: npm i -D webpack-cli
-> When using yarn: yarn add -D webpack-cli

so then I add that but get another error saying:

yarn run v1.12.3
$ webpack-dev-server --inline --hot --progress --colors --host 0.0.0.0 --devtool eval
/path/to/project/react-measure/node_modules/webpack-cli/bin/convert-argv.js:156
  	const webpackConfigurationValidationErrors = validateSchema(
  	                                             ^
TypeError: validateSchema is not a function

Any help for getting set up would be appreciated!

You can probably reproduce this if you remove your node_modules/ folder and install from scratch

@souporserious Do you yet know when your next release will be?

Apologies for the delay! I was on vacation and then needed to finish the PR that cleaned up the build system. It's published under 2.2.1 now. Thanks for the help! 🙏

Thank you! Hope your vacation was excellent

	componentWillMount() {
	this._resizeObserver = new ResizeObserver(this.measure)
	this.animationFrameID = null;
	}