格式化JSON的方法

var jsl = typeof jsl === 'undefined' ? {}: jsl;
jsl.format = (function() {
    function repeat(s, count) {
        return new Array(count + 1).join(s)
    }
    function formatJson(json) {
        var i = 0,
        il = 0,
        tab = "    ",
        newJson = "",
        indentLevel = 0,
        inString = false,
        currentChar = null;
        for (i = 0, il = json.length; i < il; i += 1) {
            currentChar = json.charAt(i);
            switch (currentChar) {
            case '{':
            case '[':
                if (!inString) {
                    newJson += currentChar + "\n" + repeat(tab, indentLevel + 1);
                    indentLevel += 1
                } else {
                    newJson += currentChar
                }
                break;
            case '}':
            case ']':
                if (!inString) {
                    indentLevel -= 1;
                    newJson += "\n" + repeat(tab, indentLevel) + currentChar
                } else {
                    newJson += currentChar
                }
                break;
            case ',':
                if (!inString) {
                    newJson += ",\n" + repeat(tab, indentLevel)
                } else {
                    newJson += currentChar
                }
                break;
            case ':':
                if (!inString) {
                    newJson += ": "
                } else {
                    newJson += currentChar
                }
                break;
            case ' ':
            case "\n":
            case "\t":
                if (inString) {
                    newJson += currentChar
                }
                break;
            case '"':
                if (i > 0 && json.charAt(i - 1) !== '\\') {
                    inString = !inString
                }
                newJson += currentChar;
                break;
            default:
                newJson += currentChar;
                break
            }
        }
        return newJson
    }
    return {
        "formatJson": formatJson
    }
} ());

调用如下：

jsonVal = jsl.format.formatJson($('#json_input').val());