在 Javascript 的递归函数中使用正则表达式进行解析

Question

I want to parse a string which contains shortcodes and push each extracted node into an array. However the recursive function I have written for this never terminates. What am I doing wrong here?

var i = 0;
var nodes = [];
var pattern = /(\[sc_(\w+)[\s\w="_-]*\])(.*)(\[\/sc_\2\])/gi;

var extractNodes = function(str, parent) {
    var m;

    if (str.indexOf('[sc_') === -1) return;

    while ((m = pattern.exec(str)) !== null) {
        nodes.push({
            id: i,
            tag: m[2],
            children: m[3],
            parentId: parent
        });
        extractNodes(m[3], i++);
    }
}

extractNodes("[sc_div][sc_span][sc_strong]Foo[/sc_strong][/sc_span][/sc_div]", -1); 

Answer 1

You've got a conflict between your while loop and the global ( g flag ) RegEx.

Each iteration of the function is sending the same str parameter. You can fix this by making the RegEx non-global by removing the g flag and while loop.

Live Demo

 var i = 0; var nodes = []; var pattern = /(\\[sc_(\\w+)[\\s\\w="_-]*\\])(.*)(\\[\\/sc_\\2\\])/i; // <-- Remove `g` flag var extractNodes = function (str, parent) { var m; if (str.indexOf('[sc_') === -1) return; if ((m = pattern.exec(str)) !== null) { nodes.push({ id: i, tag: m[2], children: m[3], parentId: parent }); extractNodes(m[3], i++); } } extractNodes("[sc_div][sc_span][sc_strong]Foo[/sc_strong][/sc_span][/sc_div]", -1); console.log(nodes); document.body.innerHTML = '<pre>' + JSON.stringify(nodes, 0, 4) + '</pre>'; // For DEMO purpose only

Console Output (Chrome):

[Object, Object, Object]
0:Object
children: "[sc_span][sc_strong]Foo[/sc_strong][/sc_span]"
id: 0
parentId: -1
tag: "div"
__proto__: Object
1:Object
children: "[sc_strong]Foo[/sc_strong]"
id: 1
parentId: 0
tag: "span"
__proto__: Object
2:Object
children: "Foo"
id: 2
parentId: 1
tag: "strong"
__proto__: Object
length: 3
__proto__: Array[0]