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AST utility module for statically analyzing JSX.

$ npm i jsx-ast-utils --save

This is a utility module to evaluate AST objects for JSX syntax. This can be super useful when writing linting rules for JSX code. It was originally in the code for eslint-plugin-jsx-a11y, however I thought it could be useful to be extracted and maintained separately so you could write new interesting rules to statically analyze JSX.

import { hasProp } from 'jsx-ast-utils';
// OR: var hasProp = require('jsx-ast-utils').hasProp;
// OR: const hasProp = require('jsx-ast-utils/hasProp');
// OR: import hasProp from 'jsx-ast-utils/hasProp';

module.exports = context => ({
  JSXOpeningElement: node => {
    const onChange = hasProp(node.attributes, 'onChange');

    if (onChange) {
      context.report({
        node,
        message: `No onChange!`
      });
    }
  }
});

1. JSX spec
2. JS spec

hasProp(props, prop, options);

Returns boolean indicating whether an prop exists as an attribute on a JSX element node.

Object - The attributes on the visited node. (Usually node.attributes).

String - A string representation of the prop you want to check for existence.

Object - An object representing options for existence checking

1. ignoreCase - automatically set to true.
2. spreadStrict - automatically set to true. This means if spread operator exists in props, it will assume the prop you are looking for is not in the spread. Example: <div {...props} /> looking for specific prop here will return false if spreadStrict is true.

hasAnyProp(props, prop, options);

Returns a boolean indicating if any of props in prop argument exist on the node.

Object - The attributes on the visited node. (Usually node.attributes).

Array - An array of strings representing the props you want to check for existence.

Object - An object representing options for existence checking

1. ignoreCase - automatically set to true.
2. spreadStrict - automatically set to true. This means if spread operator exists in props, it will assume the prop you are looking for is not in the spread. Example: <div {...props} /> looking for specific prop here will return false if spreadStrict is true.

hasEveryProp(props, prop, options);

Returns a boolean indicating if all of props in prop argument exist on the node.

Object - The attributes on the visited node. (Usually node.attributes).

Array - An array of strings representing the props you want to check for existence.

Object - An object representing options for existence checking

1. ignoreCase - automatically set to true.
2. spreadStrict - automatically set to true. This means if spread operator exists in props, it will assume the prop you are looking for is not in the spread. Example: <div {...props} /> looking for specific prop here will return false if spreadStrict is true.

getProp(props, prop, options);

Returns the JSXAttribute itself or undefined, indicating the prop is not present on the JSXOpeningElement.

Object - The attributes on the visited node. (Usually node.attributes).

String - A string representation of the prop you want to check for existence.

Object - An object representing options for existence checking

1. ignoreCase - automatically set to true.

elementType(node)

Returns the tagName associated with a JSXElement.

Object - The visited JSXElement node object.

getPropValue(prop);

Returns the value of a given attribute. Different types of attributes have their associated values in different properties on the object.

This function should return the most closely associated value with the intention of the JSX.

Object - The JSXAttribute collected by AST parser.

getLiteralPropValue(prop);

Returns the value of a given attribute. Different types of attributes have their associated values in different properties on the object.

This function should return a value only if we can extract a literal value from its attribute (i.e. values that have generic types in JavaScript - strings, numbers, booleans, etc.)

Object - The JSXAttribute collected by AST parser.

propName(prop);

Returns the name associated with a JSXAttribute. For example, given <div foo="bar" /> and the JSXAttribute for foo, this will return the string "foo".

Object - The JSXAttribute collected by AST parser.

console.log(eventHandlers);
/*
[
  'onCopy',
  'onCut',
  'onPaste',
  'onCompositionEnd',
  'onCompositionStart',
  'onCompositionUpdate',
  'onKeyDown',
  'onKeyPress',
  'onKeyUp',
  'onFocus',
  'onBlur',
  'onChange',
  'onInput',
  'onSubmit',
  'onClick',
  'onContextMenu',
  'onDblClick',
  'onDoubleClick',
  'onDrag',
  'onDragEnd',
  'onDragEnter',
  'onDragExit',
  'onDragLeave',
  'onDragOver',
  'onDragStart',
  'onDrop',
  'onMouseDown',
  'onMouseEnter',
  'onMouseLeave',
  'onMouseMove',
  'onMouseOut',
  'onMouseOver',
  'onMouseUp',
  'onSelect',
  'onTouchCancel',
  'onTouchEnd',
  'onTouchMove',
  'onTouchStart',
  'onScroll',
  'onWheel',
  'onAbort',
  'onCanPlay',
  'onCanPlayThrough',
  'onDurationChange',
  'onEmptied',
  'onEncrypted',
  'onEnded',
  'onError',
  'onLoadedData',
  'onLoadedMetadata',
  'onLoadStart',
  'onPause',
  'onPlay',
  'onPlaying',
  'onProgress',
  'onRateChange',
  'onSeeked',
  'onSeeking',
  'onStalled',
  'onSuspend',
  'onTimeUpdate',
  'onVolumeChange',
  'onWaiting',
  'onLoad',
  'onError',
  'onAnimationStart',
  'onAnimationEnd',
  'onAnimationIteration',
  'onTransitionEnd',
]
*/

Contains a flat list of common event handler props used in JSX to attach behaviors to DOM events.

The same list as eventHandlers, grouped into types.

console.log(eventHandlersByType);
/*
{
  clipboard: [ 'onCopy', 'onCut', 'onPaste' ],
  composition: [ 'onCompositionEnd', 'onCompositionStart', 'onCompositionUpdate' ],
  keyboard: [ 'onKeyDown', 'onKeyPress', 'onKeyUp' ],
  focus: [ 'onFocus', 'onBlur' ],
  form: [ 'onChange', 'onInput', 'onSubmit' ],
  mouse: [ 'onClick', 'onContextMenu', 'onDblClick', 'onDoubleClick', 'onDrag', 'onDragEnd', 'onDragEnter', 'onDragExit', 'onDragLeave', 'onDragOver', 'onDragStart', 'onDrop', 'onMouseDown', 'onMouseEnter', 'onMouseLeave', 'onMouseMove', 'onMouseOut', 'onMouseOver', 'onMouseUp' ],
  selection: [ 'onSelect' ],
  touch: [ 'onTouchCancel', 'onTouchEnd', 'onTouchMove', 'onTouchStart' ],
  ui: [ 'onScroll' ],
  wheel: [ 'onWheel' ],
  media: [ 'onAbort', 'onCanPlay', 'onCanPlayThrough', 'onDurationChange', 'onEmptied', 'onEncrypted', 'onEnded', 'onError', 'onLoadedData', 'onLoadedMetadata', 'onLoadStart', 'onPause', 'onPlay', 'onPlaying', 'onProgress', 'onRateChange', 'onSeeked', 'onSeeking', 'onStalled', 'onSuspend', 'onTimeUpdate', 'onVolumeChange', 'onWaiting' ],
  image: [ 'onLoad', 'onError' ],
  animation: [ 'onAnimationStart', 'onAnimationEnd', 'onAnimationIteration' ],
  transition: [ 'onTransitionEnd' ],
}
*/