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TiddlyWiki5/core/modules/indexers/backlinks-index.js
Rob Hoelz ae04a425c0
Add backlinks indexer (#4421)
* Add tests for backlinks

* Add backlinks indexer

* Use backlinks indexer in getTiddlerBacklinks if available

* Extract link extraction into its own method

This way we can provide an arbitrary parse tree, rather than just a
title, which will allow us to compare lists of outgoing links between
versions of a single tiddler

* Use new extractLinks method in backlinks indexer

...rather than copy-pasting the implementation

* Remove ES6-isms

TiddlyWiki needs to work with browsers that only support ES5
2020-03-26 13:15:02 +00:00

87 lines
1.8 KiB
JavaScript

/*\
title: $:/core/modules/indexers/backlinks-indexer.js
type: application/javascript
module-type: indexer
Indexes the tiddlers' backlinks
\*/
(function(){
/*jslint node: true, browser: true */
/*global modules: false */
"use strict";
function BacklinksIndexer(wiki) {
this.wiki = wiki;
}
BacklinksIndexer.prototype.init = function() {
this.index = null;
}
BacklinksIndexer.prototype.rebuild = function() {
this.index = null;
}
BacklinksIndexer.prototype._getLinks = function(tiddler) {
var parser = this.wiki.parseText(tiddler.fields.type, tiddler.fields.text, {});
if(parser) {
return this.wiki.extractLinks(parser.tree);
}
return [];
}
BacklinksIndexer.prototype.update = function(updateDescriptor) {
if(!this.index) {
return;
}
var newLinks = [],
oldLinks = [],
self = this;
if(updateDescriptor.old.exists) {
oldLinks = this._getLinks(updateDescriptor.old.tiddler);
}
if(updateDescriptor.new.exists) {
newLinks = this._getLinks(updateDescriptor.new.tiddler);
}
$tw.utils.each(oldLinks,function(link) {
if(self.index[link]) {
delete self.index[link][updateDescriptor.old.tiddler.fields.title];
}
});
$tw.utils.each(newLinks,function(link) {
if(!self.index[link]) {
self.index[link] = Object.create(null);
}
self.index[link][updateDescriptor.new.tiddler.fields.title] = true;
});
}
BacklinksIndexer.prototype.lookup = function(title) {
if(!this.index) {
this.index = Object.create(null);
var self = this;
this.wiki.forEachTiddler(function(title,tiddler) {
var links = self._getLinks(tiddler);
$tw.utils.each(links, function(link) {
if(!self.index[link]) {
self.index[link] = Object.create(null);
}
self.index[link][title] = true;
});
});
}
if(this.index[title]) {
return Object.keys(this.index[title]);
} else {
return [];
}
}
exports.BacklinksIndexer = BacklinksIndexer;
})();