lepu-test-platform-web/node_modules/echarts/lib/util/throttle.js

193 lines
5.3 KiB
JavaScript

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
var ORIGIN_METHOD = '\0__throttleOriginMethod';
var RATE = '\0__throttleRate';
var THROTTLE_TYPE = '\0__throttleType';
/**
* @public
* @param {(Function)} fn
* @param {number} [delay=0] Unit: ms.
* @param {boolean} [debounce=false]
* true: If call interval less than `delay`, only the last call works.
* false: If call interval less than `delay, call works on fixed rate.
* @return {(Function)} throttled fn.
*/
function throttle(fn, delay, debounce) {
var currCall;
var lastCall = 0;
var lastExec = 0;
var timer = null;
var diff;
var scope;
var args;
var debounceNextCall;
delay = delay || 0;
function exec() {
lastExec = new Date().getTime();
timer = null;
fn.apply(scope, args || []);
}
var cb = function () {
currCall = new Date().getTime();
scope = this;
args = arguments;
var thisDelay = debounceNextCall || delay;
var thisDebounce = debounceNextCall || debounce;
debounceNextCall = null;
diff = currCall - (thisDebounce ? lastCall : lastExec) - thisDelay;
clearTimeout(timer); // Here we should make sure that: the `exec` SHOULD NOT be called later
// than a new call of `cb`, that is, preserving the command order. Consider
// calculating "scale rate" when roaming as an example. When a call of `cb`
// happens, either the `exec` is called dierectly, or the call is delayed.
// But the delayed call should never be later than next call of `cb`. Under
// this assurance, we can simply update view state each time `dispatchAction`
// triggered by user roaming, but not need to add extra code to avoid the
// state being "rolled-back".
if (thisDebounce) {
timer = setTimeout(exec, thisDelay);
} else {
if (diff >= 0) {
exec();
} else {
timer = setTimeout(exec, -diff);
}
}
lastCall = currCall;
};
/**
* Clear throttle.
* @public
*/
cb.clear = function () {
if (timer) {
clearTimeout(timer);
timer = null;
}
};
/**
* Enable debounce once.
*/
cb.debounceNextCall = function (debounceDelay) {
debounceNextCall = debounceDelay;
};
return cb;
}
/**
* Create throttle method or update throttle rate.
*
* @example
* ComponentView.prototype.render = function () {
* ...
* throttle.createOrUpdate(
* this,
* '_dispatchAction',
* this.model.get('throttle'),
* 'fixRate'
* );
* };
* ComponentView.prototype.remove = function () {
* throttle.clear(this, '_dispatchAction');
* };
* ComponentView.prototype.dispose = function () {
* throttle.clear(this, '_dispatchAction');
* };
*
* @public
* @param {Object} obj
* @param {string} fnAttr
* @param {number} [rate]
* @param {string} [throttleType='fixRate'] 'fixRate' or 'debounce'
* @return {Function} throttled function.
*/
function createOrUpdate(obj, fnAttr, rate, throttleType) {
var fn = obj[fnAttr];
if (!fn) {
return;
}
var originFn = fn[ORIGIN_METHOD] || fn;
var lastThrottleType = fn[THROTTLE_TYPE];
var lastRate = fn[RATE];
if (lastRate !== rate || lastThrottleType !== throttleType) {
if (rate == null || !throttleType) {
return obj[fnAttr] = originFn;
}
fn = obj[fnAttr] = throttle(originFn, rate, throttleType === 'debounce');
fn[ORIGIN_METHOD] = originFn;
fn[THROTTLE_TYPE] = throttleType;
fn[RATE] = rate;
}
return fn;
}
/**
* Clear throttle. Example see throttle.createOrUpdate.
*
* @public
* @param {Object} obj
* @param {string} fnAttr
*/
function clear(obj, fnAttr) {
var fn = obj[fnAttr];
if (fn && fn[ORIGIN_METHOD]) {
obj[fnAttr] = fn[ORIGIN_METHOD];
}
}
exports.throttle = throttle;
exports.createOrUpdate = createOrUpdate;
exports.clear = clear;