Determine which props causes React components to re-render

determine-changed-props.js

import React, { Component } from 'react';

export default function withPropsChecker(WrappedComponent) {
  return class PropsChecker extends Component {
    componentWillReceiveProps(nextProps) {
      Object.keys(nextProps)
        .filter(key => {
          return nextProps[key] !== this.props[key];
        })
        .map(key => {
          console.log(
            'changed property:',
            key,
            'from',
            this.props[key],
            'to',
            nextProps[key]
          );
        });
    }
    render() {
      return <WrappedComponent {...this.props} />;
    }
  };
}

// Usage
withPropsChecker(MyComponent)

If you wanted to take it a bit further instead of simply logging the props, there’s a useful package to diff objects which will output the difference. Very useful when nothing has really changed, but simply the ref.

This is good. However, what do you think of logging changes on componentDidUpdate, instead of componentWillReceiveProps, therefore not delaying the rendering :)

@IamFonky it is giving only initial props, how can i check prop in the case of react-select change?

@kulkarnipradnyas I don't really understand your question. What do you mean by react-select change? If you use a select component, the onChange function won't trigger any changes in his own props... can you provide an example of what you try to do please?

@IamFonky I am trying it on story book and trying to check my react-select component, i wrote some consoles..it is rendering 4 time while selecting dropdown value.Thought to check due to which props its rerendering. but it is providing me props only at the time of loading only. On change event of that my react-select it is giving below.
<ReactFnCompPropsChecker
compType='DEEP'
childrenProps={{
variant: 'form-select',
optionList: options,
label: 'Name',
required: true,
loading: false,
onChange: (input: string) => console.log(input),
error: false,
errorMessage: '',
placeholder: '',
value: 'emailVerificationPending',
width: '300px'
}}
>
{() => (
<DropDown
variant={text('variant', 'form-select') as tSelectVariant}
optionList={object('optionList', options)}
label={text('label', 'Name')}
required={boolean('required', true)}
loading={boolean('loading', false)}
onChange={action('Value selected')}
error={boolean('error', false)}
errorMessage={text('errorMessage', '')}
placeholder={text('placeholder', '')}
value={text('value', 'emailVerificationPending')}
width={text('width', '300px')}
/>
)}

First render :
variant : form-select
optionList : [object Object],[object Object],[object Object]
label : Name
required : true
loading : false
onChange : function onChange(input) {
return console.log(input);
}
error : false
errorMessage :
placeholder :
value : emailVerificationPending
width : 300px

You're not using the same props you gave to the checker comp in the DropDown. So you may be recreating props and making the DropDown rerender here.

You did this :

[...]
 >
{() => (
<DropDown
[...]

But you should do this :

[...]
 >
{(props) => (
<DropDown {...props}\>
[...]

As I wrote in my first comment, use it like that :

<ReactFnCompPropsChecker childrenProps={{prop1:...,prop2:...,...}}>
  {props=>(<TestedComponent{...props}/>)}
</ReactFnCompPropsChecker>

Use the variable given back to the children component in your DropDown in order to ensure you're looking at the same values.

I hope it helped you @kulkarnipradnyas