preact
Version:
Fast 3kb React-compatible Virtual DOM library.
314 lines (278 loc) • 8.96 kB
JavaScript
import {
render as preactRender,
hydrate as preactHydrate,
options,
toChildArray,
Component
} from 'preact';
import {
useCallback,
useContext,
useDebugValue,
useEffect,
useId,
useImperativeHandle,
useLayoutEffect,
useMemo,
useReducer,
useRef,
useState
} from 'preact/hooks';
import {
useDeferredValue,
useInsertionEffect,
useSyncExternalStore,
useTransition
} from './index';
export const REACT_ELEMENT_TYPE =
(typeof Symbol != 'undefined' && Symbol.for && Symbol.for('react.element')) ||
0xeac7;
const CAMEL_PROPS =
/^(?:accent|alignment|arabic|baseline|cap|clip(?!PathU)|color|dominant|fill|flood|font|glyph(?!R)|horiz|image(!S)|letter|lighting|marker(?!H|W|U)|overline|paint|pointer|shape|stop|strikethrough|stroke|text(?!L)|transform|underline|unicode|units|v|vector|vert|word|writing|x(?!C))[A-Z]/;
const ON_ANI = /^on(Ani|Tra|Tou|BeforeInp|Compo)/;
const CAMEL_REPLACE = /[A-Z0-9]/g;
const IS_DOM = typeof document !== 'undefined';
// Input types for which onchange should not be converted to oninput.
// type="file|checkbox|radio", plus "range" in IE11.
// (IE11 doesn't support Symbol, which we use here to turn `rad` into `ra` which matches "range")
const onChangeInputType = type =>
(typeof Symbol != 'undefined' && typeof Symbol() == 'symbol'
? /fil|che|rad/
: /fil|che|ra/
).test(type);
// Some libraries like `react-virtualized` explicitly check for this.
Component.prototype.isReactComponent = {};
// `UNSAFE_*` lifecycle hooks
// Preact only ever invokes the unprefixed methods.
// Here we provide a base "fallback" implementation that calls any defined UNSAFE_ prefixed method.
// - If a component defines its own `componentDidMount()` (including via defineProperty), use that.
// - If a component defines `UNSAFE_componentDidMount()`, `componentDidMount` is the alias getter/setter.
// - If anything assigns to an `UNSAFE_*` property, the assignment is forwarded to the unprefixed property.
// See https://github.com/preactjs/preact/issues/1941
[
'componentWillMount',
'componentWillReceiveProps',
'componentWillUpdate'
].forEach(key => {
Object.defineProperty(Component.prototype, key, {
configurable: true,
get() {
return this['UNSAFE_' + key];
},
set(v) {
Object.defineProperty(this, key, {
configurable: true,
writable: true,
value: v
});
}
});
});
/**
* Proxy render() since React returns a Component reference.
* @param {import('./internal').VNode} vnode VNode tree to render
* @param {import('./internal').PreactElement} parent DOM node to render vnode tree into
* @param {() => void} [callback] Optional callback that will be called after rendering
* @returns {import('./internal').Component | null} The root component reference or null
*/
export function render(vnode, parent, callback) {
// React destroys any existing DOM nodes, see #1727
// ...but only on the first render, see #1828
if (parent._children == null) {
parent.textContent = '';
}
preactRender(vnode, parent);
if (typeof callback == 'function') callback();
return vnode ? vnode._component : null;
}
export function hydrate(vnode, parent, callback) {
preactHydrate(vnode, parent);
if (typeof callback == 'function') callback();
return vnode ? vnode._component : null;
}
let oldEventHook = options.event;
options.event = e => {
if (oldEventHook) e = oldEventHook(e);
e.persist = empty;
e.isPropagationStopped = isPropagationStopped;
e.isDefaultPrevented = isDefaultPrevented;
return (e.nativeEvent = e);
};
function empty() {}
function isPropagationStopped() {
return this.cancelBubble;
}
function isDefaultPrevented() {
return this.defaultPrevented;
}
const classNameDescriptorNonEnumberable = {
enumerable: false,
configurable: true,
get() {
return this.class;
}
};
function handleDomVNode(vnode) {
let props = vnode.props,
type = vnode.type,
normalizedProps = {};
let isNonDashedType = type.indexOf('-') === -1;
for (let i in props) {
let value = props[i];
if (
(i === 'value' && 'defaultValue' in props && value == null) ||
// Emulate React's behavior of not rendering the contents of noscript tags on the client.
(IS_DOM && i === 'children' && type === 'noscript') ||
i === 'class' ||
i === 'className'
) {
// Skip applying value if it is null/undefined and we already set
// a default value
continue;
}
let lowerCased = i.toLowerCase();
if (i === 'defaultValue' && 'value' in props && props.value == null) {
// `defaultValue` is treated as a fallback `value` when a value prop is present but null/undefined.
// `defaultValue` for Elements with no value prop is the same as the DOM defaultValue property.
i = 'value';
} else if (i === 'download' && value === true) {
// Calling `setAttribute` with a truthy value will lead to it being
// passed as a stringified value, e.g. `download="true"`. React
// converts it to an empty string instead, otherwise the attribute
// value will be used as the file name and the file will be called
// "true" upon downloading it.
value = '';
} else if (lowerCased === 'translate' && value === 'no') {
value = false;
} else if (lowerCased[0] === 'o' && lowerCased[1] === 'n') {
if (lowerCased === 'ondoubleclick') {
i = 'ondblclick';
} else if (
lowerCased === 'onchange' &&
(type === 'input' || type === 'textarea') &&
!onChangeInputType(props.type)
) {
lowerCased = i = 'oninput';
} else if (lowerCased === 'onfocus') {
i = 'onfocusin';
} else if (lowerCased === 'onblur') {
i = 'onfocusout';
} else if (ON_ANI.test(i)) {
i = lowerCased;
}
} else if (isNonDashedType && CAMEL_PROPS.test(i)) {
i = i.replace(CAMEL_REPLACE, '-$&').toLowerCase();
} else if (value === null) {
value = undefined;
}
// Add support for onInput and onChange, see #3561
// if we have an oninput prop already change it to oninputCapture
if (lowerCased === 'oninput') {
i = lowerCased;
if (normalizedProps[i]) {
i = 'oninputCapture';
}
}
normalizedProps[i] = value;
}
// Add support for array select values: <select multiple value={[]} />
if (
type == 'select' &&
normalizedProps.multiple &&
Array.isArray(normalizedProps.value)
) {
// forEach() always returns undefined, which we abuse here to unset the value prop.
normalizedProps.value = toChildArray(props.children).forEach(child => {
child.props.selected =
normalizedProps.value.indexOf(child.props.value) != -1;
});
}
// Adding support for defaultValue in select tag
if (type == 'select' && normalizedProps.defaultValue != null) {
normalizedProps.value = toChildArray(props.children).forEach(child => {
if (normalizedProps.multiple) {
child.props.selected =
normalizedProps.defaultValue.indexOf(child.props.value) != -1;
} else {
child.props.selected =
normalizedProps.defaultValue == child.props.value;
}
});
}
if (props.class && !props.className) {
normalizedProps.class = props.class;
Object.defineProperty(
normalizedProps,
'className',
classNameDescriptorNonEnumberable
);
} else if (props.className && !props.class) {
normalizedProps.class = normalizedProps.className = props.className;
} else if (props.class && props.className) {
normalizedProps.class = normalizedProps.className = props.className;
}
vnode.props = normalizedProps;
}
let oldVNodeHook = options.vnode;
options.vnode = vnode => {
// only normalize props on Element nodes
if (typeof vnode.type === 'string') {
handleDomVNode(vnode);
}
vnode.$$typeof = REACT_ELEMENT_TYPE;
if (oldVNodeHook) oldVNodeHook(vnode);
};
// Only needed for react-relay
let currentComponent;
const oldBeforeRender = options._render;
options._render = function (vnode) {
if (oldBeforeRender) {
oldBeforeRender(vnode);
}
currentComponent = vnode._component;
};
const oldDiffed = options.diffed;
/** @type {(vnode: import('./internal').VNode) => void} */
options.diffed = function (vnode) {
if (oldDiffed) {
oldDiffed(vnode);
}
const props = vnode.props;
const dom = vnode._dom;
if (
dom != null &&
vnode.type === 'textarea' &&
'value' in props &&
props.value !== dom.value
) {
dom.value = props.value == null ? '' : props.value;
}
currentComponent = null;
};
// This is a very very private internal function for React it
// is used to sort-of do runtime dependency injection.
export const __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED = {
ReactCurrentDispatcher: {
current: {
readContext(context) {
return currentComponent._globalContext[context._id].props.value;
},
useCallback,
useContext,
useDebugValue,
useDeferredValue,
useEffect,
useId,
useImperativeHandle,
useInsertionEffect,
useLayoutEffect,
useMemo,
// useMutableSource, // experimental-only and replaced by uSES, likely not worth supporting
useReducer,
useRef,
useState,
useSyncExternalStore,
useTransition
}
}
};