Merge pull request #844 from lvscar/master

Adding a search method to section for find out result spanning multiple nodes.
futurepress · May 14, 2020 · 5c04784 · 5c04784
2 parents 9bd8440 + f5022af
commit 5c04784
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Showing 2 changed files with 124 additions and 11 deletions.
diff --git a/src/section.js b/src/section.js
@@ -173,6 +173,75 @@ class Section {
 		return matches;
 	};
 
+
+	/**
+	 * Search a string in multiple sequential Element of the section. If the document.createTreeWalker api is missed(eg: IE8), use `find` as a fallback.
+	 * @param  {string} _query The query string to search
+	 * @param  {int} maxSeqEle The maximum number of Element that are combined for search, defualt value is 5.
+	 * @return {object[]} A list of matches, with form {cfi, excerpt}
+	 */
+	search(_query , maxSeqEle = 5){
+		if (typeof(document.createTreeWalker) == "undefined") {
+			return this.find(_query);
+		}
+		let matches = [];
+		const excerptLimit = 150;
+		const section = this;
+		const query = _query.toLowerCase();
+		const search = function(nodeList){
+			const textWithCase =  nodeList.reduce((acc ,current)=>{
+				return acc + current.textContent;
+			},"");
+			const text = textWithCase.toLowerCase();
+			const pos = text.indexOf(query);
+			if (pos != -1){
+				const startNodeIndex = 0 , endPos = pos + query.length;
+				let endNodeIndex = 0 , l = 0;
+				if (pos < nodeList[startNodeIndex].length){
+					let cfi;
+					while( endNodeIndex < nodeList.length - 1 ){
+						l += nodeList[endNodeIndex].length;
+						if ( endPos <= l){
+							break;
+						}
+						endNodeIndex += 1;
+					}
+
+					let startNode = nodeList[startNodeIndex] , endNode = nodeList[endNodeIndex];
+					let range = section.document.createRange();
+					range.setStart(startNode,pos);
+					let beforeEndLengthCount =  nodeList.slice(0, endNodeIndex).reduce((acc,current)=>{return acc+current.textContent.length;},0) ;
+					range.setEnd(endNode, beforeEndLengthCount > endPos ? endPos : endPos - beforeEndLengthCount );
+					cfi = section.cfiFromRange(range);
+
+					let excerpt = nodeList.slice(0, endNodeIndex+1).reduce((acc,current)=>{return acc+current.textContent ;},"");
+					if (excerpt.length > excerptLimit){
+						excerpt = excerpt.substring(pos - excerptLimit/2, pos + excerptLimit/2);
+						excerpt = "..." + excerpt + "...";
+					}
+					matches.push({
+						cfi: cfi,
+						excerpt: excerpt
+					});
+				}
+			}
+		}
+
+		const treeWalker = document.createTreeWalker(section.document, NodeFilter.SHOW_TEXT, null, false);
+		let node , nodeList = [];
+		while (node = treeWalker.nextNode()) {
+			nodeList.push(node);
+			if (nodeList.length == maxSeqEle){
+				search(nodeList.slice(0 , maxSeqEle));
+				nodeList = nodeList.slice(1, maxSeqEle);
+			}
+		}
+		if (nodeList.length > 0){
+			search(nodeList);
+		}
+		return matches;
+	}
+
 	/**
 	* Reconciles the current chapters layout properies with
 	* the global layout properities.

diff --git a/test/section.js b/test/section.js
@@ -7,10 +7,14 @@ describe("section", function() {
                 return book.ready.then(function() {
                         var section = book.section("chapter_001.xhtml");
                         return section.load().then(function() {
-                                var results = section.find("they were filled with cupboards and book-shelves");
-                                assert.equal(results.length, 1);
-                                assert.equal(results[0].cfi, "epubcfi(/6/8[chapter_001]!/4/2/16,/1:275,/1:323)");
-                                assert.equal(results[0].excerpt, "... see anything; then she looked at the sides of the well and\n\t\tnoticed that they were filled with cupboards and book-shelves; here and there she saw\n\t\t...");
+                                const queryString = "they were filled with cupboards and book-shelves";
+                                const findResults = section.find(queryString);
+                                const searchResults = section.search(queryString);
+                                [findResults , searchResults].forEach( (results)=>{
+                                        assert.equal(results.length, 1);
+                                        assert.equal(results[0].cfi, "epubcfi(/6/8[chapter_001]!/4/2/16,/1:275,/1:323)");
+                                        assert.equal(results[0].excerpt, "... see anything; then she looked at the sides of the well and\n\t\tnoticed that they were filled with cupboards and book-shelves; here and there she saw\n\t\t...");
+                                });
                         });
                 });
         });
@@ -20,14 +24,54 @@ describe("section", function() {
                 return book.ready.then(function() {
                         var section = book.section("chapter_001.xhtml");
                         return section.load().then(function() {
-                                var results = section.find("white rabbit");
-                                assert.equal(results.length, 2);
-                                assert.equal(results[0].cfi, "epubcfi(/6/8[chapter_001]!/4/2/8,/1:240,/1:252)");
-                                assert.equal(results[0].excerpt, "...e worth the trouble of getting up and picking the daisies, when suddenly a White Rabbit with pink eyes ran close by her....");
-                                assert.equal(results[1].cfi, "epubcfi(/6/8[chapter_001]!/4/2/20,/1:148,/1:160)");
-                                assert.equal(results[1].excerpt, "...ut it was\n\t\tall dark overhead; before her was another long passage and the White Rabbit was still\n\t\tin sight, hurrying down it. There was not a moment...");
-                       });
+                                const queryString = "white rabbit";
+                                const findResults = section.find(queryString);
+                                const searchResults = section.search(queryString);
+                                [findResults , searchResults].forEach( (results)=>{
+                                        assert.equal(results.length, 2);
+                                        assert.equal(results[0].cfi, "epubcfi(/6/8[chapter_001]!/4/2/8,/1:240,/1:252)");
+                                        assert.equal(results[0].excerpt, "...e worth the trouble of getting up and picking the daisies, when suddenly a White Rabbit with pink eyes ran close by her....");
+                                        assert.equal(results[1].cfi, "epubcfi(/6/8[chapter_001]!/4/2/20,/1:148,/1:160)");
+                                        assert.equal(results[1].excerpt, "...ut it was\n\t\tall dark overhead; before her was another long passage and the White Rabbit was still\n\t\tin sight, hurrying down it. There was not a moment...");
+                                });
+                        });
                 });
 
         });
+
+        it("finds result that spanning multiple document nodes, tag at ending", function() {
+                var book = ePub("./fixtures/alice/", {width: 400, height: 400});
+                return book.ready.then(function() {
+                        var section = book.section("chapter_010.xhtml");
+                        return section.load().then(function() {
+                                const queryString = "I beg";
+
+                                const findResult = section.find(queryString);
+                                assert.equal(findResult.length, 0);
+
+                                const searchResults = section.search(queryString);
+                                assert.equal(searchResults.length, 1);
+                                assert.equal(searchResults[0].cfi, "epubcfi(/6/26[chapter_010]!/4/2/6,/1:5,/2/1:3)");
+                                assert.equal(searchResults[0].excerpt,'"Oh, I beg');
+                        });
+                });
+        });
+
+        it("finds result that spanning multiple document nodes, tag at middle", function() {
+                var book = ePub("./fixtures/alice/", {width: 400, height: 400});
+                return book.ready.then(function() {
+                        var section = book.section("chapter_010.xhtml");
+                        return section.load().then(function() {
+                                const queryString = "I beg your pardon";
+
+                                const findResult = section.find(queryString);
+                                assert.equal(findResult.length, 0);
+
+                                const searchResults = section.search(queryString);
+                                assert.equal(searchResults.length, 1);
+                                assert.equal(searchResults[0].cfi, "epubcfi(/6/26[chapter_010]!/4/2/6,/1:5,/3:12)");
+                                assert.equal(searchResults[0].excerpt,'"Oh, I beg your pardon!" she exclaimed in a tone of great dismay.');
+                        });
+                });
+        });
 });