84 lines
2.5 KiB
JavaScript
84 lines
2.5 KiB
JavaScript
'use strict';
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/*@
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Ox.cache <f> Memoize a function
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fn <f> function
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options <o>
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async <b|false> function is async, last argument must be callback
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key <f|JSON.stringify> return key for arguments
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<script>
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Ox.test.fn = Ox.cache(function(n) { return n * Math.random(); });
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</script>
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> Ox.test.fn(10) == Ox.test.fn(10);
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true
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> Ox.test.fn(10) == Ox.test.fn.clear()(10);
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false
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@*/
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// TODO: add async test
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Ox.cache = function(fn, options) {
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var cache = {},
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ret = function() {
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options = Ox.extend({
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async: false,
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key: JSON.stringify
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}, options || {});
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var args = Ox.toArray(arguments), key = options.key(args);
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function callback() {
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// cache all arguments passed to callback
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cache[key] = Ox.toArray(arguments);
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// call the original callback
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Ox.last(args).apply(this, arguments);
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}
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if (options.async) {
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if (!(key in cache)) {
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// call function with patched callback
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fn.apply(this, args.slice(0, -1).concat(callback));
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} else {
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// call callback with cached arguments
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setTimeout(function() {
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callback.apply(this, cache[key]);
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});
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}
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} else {
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if (!(key in cache)) {
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cache[key] = fn.apply(this, args);
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}
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return cache[key];
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}
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};
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ret.clear = function() {
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if (arguments.length == 0) {
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cache = {};
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} else {
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Ox.makeArray(arguments).forEach(function(key) {
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delete cache[key];
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});
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}
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return ret;
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};
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return ret;
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};
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/*@
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Ox.identity <f> Returns its first argument
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This can be used as a default iterator
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> Ox.identity(Infinity)
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Infinity
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@*/
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Ox.identity = function(value) {
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return value;
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};
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/*@
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Ox.noop <f> Returns undefined and calls optional callback without arguments
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This can be used as a default iterator in an asynchronous loop, or to
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combine a synchronous and an asynchronous code path.
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> Ox.noop(1, 2, 3)
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undefined
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> Ox.noop(1, 2, 3, function() { Ox.test(arguments.length, 0); })
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undefined
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@*/
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Ox.noop = function() {
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var callback = Ox.last(arguments);
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Ox.isFunction(callback) && callback();
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};
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