root/human-readable-json/human-readable-json.user.js

// Human Readable JSON Greasemonkey Script v0.1.1
// Copyright 2007 Gerald Kaszuba
// Released under the GPL license
// http://www.gnu.org/copyleft/gpl.html
// --------------------------------------------------------------------
//
// ==UserScript==
// @name          Human Readable JSON
// @namespace     http://misc.slowchop.com/misc/wiki/HumanReadableJSONGreasemonkey
// @description   Adds line breaks and indentation to a JSON response, making it easier to read.
// @include       http://misc.slowchop.com/misc/wiki/HumanReadableJSONGreasemonkey/JsonExample?format=txt
// ==/UserScript==

/*
JSON pretty print borrowed and slightly modified from http://www.matsblog.com/stories/2075888/
*/
(function () {
    var INTEND = "    ";
    var NEWLINE = "\n";
    var pPr = false;
    var intendLevel = 0;
    var intend = function(a) {
        if (!pPr) return a;
        for (var l=0; l<intendLevel; l++) {
            a[a.length] = INTEND;
        }
        return a;
    };

    var newline = function(a) {
        if (pPr) a[a.length] = NEWLINE;
        return a;
    };

    var m = {
            '\b': '\\b',
            '\t': '\\t',
            '\n': '\\n',
            '\f': '\\f',
            '\r': '\\r',
            '"' : '\\"',
            '\\': '\\\\'
        },
        s = {
            array: function (x) {
                var a = ['['], b, f, i, l = x.length, v;
                a = newline(a);
                intendLevel++;
                for (i = 0; i < l; i += 1) {
                    v = x[i];
                    f = s[typeof v];
                    if (f) {
                        v = f(v);
                        if (typeof v == 'string') {
                            if (b) {
                                a[a.length] = ',';
                                a = newline(a);
                            }
                            a = intend(a);
                            a[a.length] = v;
                            b = true;
                        }
                    }
                }
                intendLevel--;
                a = newline(a);
                a = intend(a);
                a[a.length] = ']';
                return a.join('');
            },
            'boolean': function (x) {
                return String(x);
            },
            'null': function (x) {
                return "null";
            },
            number: function (x) {
                return isFinite(x) ? String(x) : 'null';
            },
            object: function (x, formatedOutput) {
                if (x) {
                    if (x instanceof Array) {
                        return s.array(x);
                    }
                    var a = ['{'], b, f, i, v;
                    a = newline(a);
                    intendLevel++;
                    for (i in x) {
                        v = x[i];
                        f = s[typeof v];
                        if (f) {
                            v = f(v);
                            if (typeof v == 'string') {
                                if (b) {
                                    a[a.length] = ',';
                                    a = newline(a);
                                }
                                a = intend(a);
                                a.push(s.string(i), ((pPr) ? ': ' : ':'), v);
                                b = true;
                            }
                        }
                    }
                    intendLevel--;
                    a = newline(a);
                    a = intend(a);
                    a[a.length] = '}';
                    return a.join('');
                }
                return 'null';
            },
            string: function (x) {
                if (/["\\\x00-\x1f]/.test(x)) {
                    x = x.replace(/([\x00-\x1f\\"])/g, function(a, b) {
                        var c = m[b];
                        if (c) {
                            return c;
                        }
                        c = b.charCodeAt();
                        return '\\u00' +
                            Math.floor(c / 16).toString(16) +
                            (c % 16).toString(16);
                    });
                }
                return '"' + x + '"';
            }
        };

    Object.prototype.toJSONString = function (prettyPrint) {
        pPr = prettyPrint;
        return s.object(this);
    };

    Array.prototype.toJSONString = function (prettyPrint) {
        pPr = prettyPrint;
        return s.array(this);
    };
})();

String.prototype.parseJSON = function () {
    try {
        return !(/[^,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]/.test(
                this.replace(/"(\\.|[^"\\])*"/g, ''))) &&
            eval('(' + this + ')');
    } catch (e) {
        return false;
    }
};

window.addEventListener(
    'load', 
    function() {
        jsonTag = document.getElementsByTagName('pre')[0];
        if (!jsonTag) return;
        jsonText = jsonTag.textContent;
        jsonObj = jsonText.parseJSON();
        prettyJson = jsonObj.toJSONString(true);
        jsonTag.textContent = prettyJson;
    },
    true);

// vim: ts=4 sw=4 expandtab