mirror of
https://github.com/Jermolene/TiddlyWiki5
synced 2024-07-04 19:23:29 +00:00
f60d0ef109
Fixes #5246. Now the reduce operator and :reduce filter run prefix will both return empty output when their input is empty, so that both can be chained together with the else operator or :else prefix.
59 lines
1.4 KiB
JavaScript
59 lines
1.4 KiB
JavaScript
/*\
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title: $:/core/modules/filters/reduce.js
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type: application/javascript
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module-type: filteroperator
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Filter operator evaluates a subfilter for each item, making the running total available in the variable `accumulator`, and the current index available in the variable `index`
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\*/
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(function(){
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/*jslint node: true, browser: true */
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/*global $tw: false */
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"use strict";
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/*
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Export our filter function
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*/
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exports.reduce = function(source,operator,options) {
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// Accumulate the list
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var results = [];
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source(function(tiddler,title) {
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results.push(title);
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});
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// Run the filter over each item
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var filterFn = options.wiki.compileFilter(operator.operand),
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accumulator = operator.operands[1] || "";
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for(var index=0; index<results.length; index++) {
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var title = results[index],
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list = filterFn.call(options.wiki,options.wiki.makeTiddlerIterator([title]),{
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getVariable: function(name) {
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switch(name) {
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case "currentTiddler":
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return "" + title;
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case "accumulator":
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return "" + accumulator;
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case "index":
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return "" + index;
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case "revIndex":
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return "" + (results.length - 1 - index);
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case "length":
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return "" + results.length;
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default:
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return options.widget.getVariable(name);
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}
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}
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});
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if(list.length > 0) {
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accumulator = "" + list[0];
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}
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}
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if(results.length > 0) {
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return [accumulator];
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} else {
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return [];
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}
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};
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})();
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