如何获取文本节点内字符串的起始偏移量？

Question

I am using Tree walker approach to get node list of document . My source is like following:

var treeWalker = document.createTreeWalker(document.body, NodeFilter.SHOW_TEXT | NodeFilter.SHOW_ELEMENT);
//treeWalker.currentNode = [set the starting node];
while (treeWalker.nextNode()){
    var presentNode = treeWalker.currentNode;
    if(presentNode.nodeType === 3  && presentNode.nodeValue.replace(/^\s+|\s+$/g, '')){
        //Getting here present node value.      
    }
}

Suppose presentNode Value is I am novice in javascript. I need start offset and end offset of novice string. How can I get these values in javascript? Can anyone support me?

Answer 1

You can use indexOf and length :

 var positionOfNovice = "I am novice in javascript.".indexOf('novice'); var novicePos = { start: positionOfNovice, end: positionOfNovice + 'novice'.length }; var result = document.querySelector('#result'); result.innerHTML = 'String: "I am novice in javascript."\\n\\nPosition of "novice": \\n' + JSON.stringify(novicePos, null, ' '); // more generic: create a String extension: String.prototype.getWord = getWord; result.innerHTML += '\\n\\nUsing extension:\\n' + JSON.stringify("I am novice in javascript.".getWord('novice'), null, ' '); function getWord(word) { var pos = this.indexOf(word); return { string: this, word: word + (pos < 0 ? ' NOT FOUND' : ''), startPosition: pos > -1 ? pos : null, endPosition: pos > -1 ? pos + word.length : null } } 

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