element-web/src/Velociraptor.js
2019-11-28 19:36:30 -07:00

151 lines
6.1 KiB
JavaScript

const React = require('react');
const ReactDom = require('react-dom');
import PropTypes from 'prop-types';
const Velocity = require('velocity-animate');
/**
* The Velociraptor contains components and animates transitions with velocity.
* It will only pick up direct changes to properties ('left', currently), and so
* will not work for animating positional changes where the position is implicit
* from DOM order. This makes it a lot simpler and lighter: if you need fully
* automatic positional animation, look at react-shuffle or similar libraries.
*/
export default class Velociraptor extends React.Component {
static propTypes = {
// either a list of child nodes, or a single child.
children: PropTypes.any,
// optional transition information for changing existing children
transition: PropTypes.object,
// a list of state objects to apply to each child node in turn
startStyles: PropTypes.array,
// a list of transition options from the corresponding startStyle
enterTransitionOpts: PropTypes.array,
};
static defaultProps = {
startStyles: [],
enterTransitionOpts: [],
};
constructor(props) {
super(props);
this.nodes = {};
this._updateChildren(this.props.children);
}
componentDidUpdate() {
this._updateChildren(this.props.children);
}
_updateChildren(newChildren) {
const oldChildren = this.children || {};
this.children = {};
React.Children.toArray(newChildren).forEach((c) => {
if (oldChildren[c.key]) {
const old = oldChildren[c.key];
const oldNode = ReactDom.findDOMNode(this.nodes[old.key]);
if (oldNode && oldNode.style.left !== c.props.style.left) {
Velocity(oldNode, { left: c.props.style.left }, this.props.transition).then(() => {
// special case visibility because it's nonsensical to animate an invisible element
// so we always hidden->visible pre-transition and visible->hidden after
if (oldNode.style.visibility === 'visible' && c.props.style.visibility === 'hidden') {
oldNode.style.visibility = c.props.style.visibility;
}
});
//console.log("translation: "+oldNode.style.left+" -> "+c.props.style.left);
}
if (oldNode && oldNode.style.visibility === 'hidden' && c.props.style.visibility === 'visible') {
oldNode.style.visibility = c.props.style.visibility;
}
// clone the old element with the props (and children) of the new element
// so prop updates are still received by the children.
this.children[c.key] = React.cloneElement(old, c.props, c.props.children);
} else {
// new element. If we have a startStyle, use that as the style and go through
// the enter animations
const newProps = {};
const restingStyle = c.props.style;
const startStyles = this.props.startStyles;
if (startStyles.length > 0) {
const startStyle = startStyles[0];
newProps.style = startStyle;
// console.log("mounted@startstyle0: "+JSON.stringify(startStyle));
}
newProps.ref = ((n) => this._collectNode(
c.key, n, restingStyle,
));
this.children[c.key] = React.cloneElement(c, newProps);
}
});
}
_collectNode(k, node, restingStyle) {
if (
node &&
this.nodes[k] === undefined &&
this.props.startStyles.length > 0
) {
const startStyles = this.props.startStyles;
const transitionOpts = this.props.enterTransitionOpts;
const domNode = ReactDom.findDOMNode(node);
// start from startStyle 1: 0 is the one we gave it
// to start with, so now we animate 1 etc.
for (var i = 1; i < startStyles.length; ++i) {
Velocity(domNode, startStyles[i], transitionOpts[i-1]);
/*
console.log("start:",
JSON.stringify(transitionOpts[i-1]),
"->",
JSON.stringify(startStyles[i]),
);
*/
}
// and then we animate to the resting state
Velocity(domNode, restingStyle,
transitionOpts[i-1])
.then(() => {
// once we've reached the resting state, hide the element if
// appropriate
domNode.style.visibility = restingStyle.visibility;
});
/*
console.log("enter:",
JSON.stringify(transitionOpts[i-1]),
"->",
JSON.stringify(restingStyle));
*/
} else if (node === null) {
// Velocity stores data on elements using the jQuery .data()
// method, and assumes you'll be using jQuery's .remove() to
// remove the element, but we don't use jQuery, so we need to
// blow away the element's data explicitly otherwise it will leak.
// This uses Velocity's internal jQuery compatible wrapper.
// See the bug at
// https://github.com/julianshapiro/velocity/issues/300
// and the FAQ entry, "Preventing memory leaks when
// creating/destroying large numbers of elements"
// (https://github.com/julianshapiro/velocity/issues/47)
const domNode = ReactDom.findDOMNode(this.nodes[k]);
if (domNode) Velocity.Utilities.removeData(domNode);
}
this.nodes[k] = node;
}
render() {
return (
<span>
{ Object.values(this.children) }
</span>
);
}
}