/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview JSON utility functions.
*/
goog.provide('goog.json');
goog.provide('goog.json.Replacer');
goog.provide('goog.json.Reviver');
goog.provide('goog.json.Serializer');
/**
* @define {boolean} If true, use the native JSON parsing API.
* NOTE: The default `goog.json.parse` implementation is able to handle
* invalid JSON. JSPB used to produce invalid JSON which is not the case
* anymore so this is safe to enable for parsing JSPB. Using native JSON is
* faster and safer than the default implementation using `eval`.
*/
goog.json.USE_NATIVE_JSON = goog.define('goog.json.USE_NATIVE_JSON', false);
/**
* @define {boolean} If true, try the native JSON parsing API first. If it
* fails, log an error and use `eval` instead. This is useful when
* transitioning to `goog.json.USE_NATIVE_JSON`. The error logger needs to
* be set by `goog.json.setErrorLogger`. If it is not set then the error
* is ignored.
*/
goog.json.TRY_NATIVE_JSON = goog.define('goog.json.TRY_NATIVE_JSON', true);
/**
* Tests if a string is an invalid JSON string. This only ensures that we are
* not using any invalid characters
* @param {string} s The string to test.
* @return {boolean} True if the input is a valid JSON string.
*/
goog.json.isValid = function(s) {
'use strict';
// All empty whitespace is not valid.
if (/^\s*$/.test(s)) {
return false;
}
// This is taken from http://www.json.org/json2.js which is released to the
// public domain.
// Changes: We dissallow \u2028 Line separator and \u2029 Paragraph separator
// inside strings. We also treat \u2028 and \u2029 as whitespace which they
// are in the RFC but IE and Safari does not match \s to these so we need to
// include them in the reg exps in all places where whitespace is allowed.
// We allowed \x7f inside strings because some tools don't escape it,
// e.g. http://www.json.org/java/org/json/JSONObject.java
// Parsing happens in three stages. In the first stage, we run the text
// against regular expressions that look for non-JSON patterns. We are
// especially concerned with '()' and 'new' because they can cause invocation,
// and '=' because it can cause mutation. But just to be safe, we want to
// reject all unexpected forms.
// We split the first stage into 4 regexp operations in order to work around
// crippling inefficiencies in IE's and Safari's regexp engines. First we
// replace all backslash pairs with '@' (a non-JSON character). Second, we
// replace all simple value tokens with ']' characters, but only when followed
// by a colon, comma, closing bracket or end of string. Third, we delete all
// open brackets that follow a colon or comma or that begin the text. Finally,
// we look to see that the remaining characters are only whitespace or ']' or
// ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.
// Don't make these static since they have the global flag.
const backslashesRe = /\\["\\\/bfnrtu]/g;
const simpleValuesRe =
/(?:"[^"\\\n\r\u2028\u2029\x00-\x08\x0a-\x1f]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?)[\s\u2028\u2029]*(?=:|,|]|}|$)/g;
const openBracketsRe = /(?:^|:|,)(?:[\s\u2028\u2029]*\[)+/g;
const remainderRe = /^[\],:{}\s\u2028\u2029]*$/;
return remainderRe.test(
s.replace(backslashesRe, '@')
.replace(simpleValuesRe, ']')
.replace(openBracketsRe, ''));
};
/**
* Logs a parsing error in `JSON.parse` solvable by using `eval`
* if `goog.json.TRY_NATIVE_JSON` is enabled.
* @private {function(string, !Error)} The first parameter is the error message,
* the second is the exception thrown by `JSON.parse`.
*/
goog.json.errorLogger_ = goog.nullFunction;
/**
* Sets an error logger to use if there's a recoverable parsing error and
* `goog.json.TRY_NATIVE_JSON` is enabled.
* @param {function(string, !Error)} errorLogger The first parameter is the
* error message, the second is the exception thrown by `JSON.parse`.
*/
goog.json.setErrorLogger = function(errorLogger) {
'use strict';
goog.json.errorLogger_ = errorLogger;
};
/**
* Parses a JSON string and returns the result. This throws an exception if
* the string is an invalid JSON string.
*
* Note that this is very slow on large strings. Use JSON.parse if possible.
*
* @param {*} s The JSON string to parse.
* @throws Error if s is invalid JSON.
* @return {Object} The object generated from the JSON string, or null.
* @deprecated Use JSON.parse.
*/
goog.json.parse = goog.json.USE_NATIVE_JSON ?
/** @type {function(*):Object} */ (goog.global['JSON']['parse']) :
function(s) {
'use strict';
let error;
if (goog.json.TRY_NATIVE_JSON) {
try {
return goog.global['JSON']['parse'](s);
} catch (ex) {
error = ex;
}
}
const o = String(s);
if (goog.json.isValid(o)) {
try {
const result = /** @type {?Object} */ (eval('(' + o + ')'));
if (error) {
goog.json.errorLogger_('Invalid JSON: ' + o, error);
}
return result;
} catch (ex) {
}
}
throw new Error('Invalid JSON string: ' + o);
};
/**
* JSON replacer, as defined in Section 15.12.3 of the ES5 spec.
* @see http://ecma-international.org/ecma-262/5.1/#sec-15.12.3
*
* TODO(nicksantos): Array should also be a valid replacer.
*
* @typedef {function(this:Object, string, *): *}
*/
goog.json.Replacer;
/**
* JSON reviver, as defined in Section 15.12.2 of the ES5 spec.
* @see http://ecma-international.org/ecma-262/5.1/#sec-15.12.3
*
* @typedef {function(this:Object, string, *): *}
*/
goog.json.Reviver;
/**
* Serializes an object or a value to a JSON string.
*
* @param {*} object The object to serialize.
* @param {?goog.json.Replacer=} opt_replacer A replacer function
* called for each (key, value) pair that determines how the value
* should be serialized. By defult, this just returns the value
* and allows default serialization to kick in.
* @throws Error if there are loops in the object graph.
* @return {string} A JSON string representation of the input.
*/
goog.json.serialize = goog.json.USE_NATIVE_JSON ?
/** @type {function(*, ?goog.json.Replacer=):string} */
(goog.global['JSON']['stringify']) :
function(object, opt_replacer) {
'use strict';
// NOTE(nicksantos): Currently, we never use JSON.stringify.
//
// The last time I evaluated this, JSON.stringify had subtle bugs and
// behavior differences on all browsers, and the performance win was not
// large enough to justify all the issues. This may change in the future
// as browser implementations get better.
//
// assertSerialize in json_test contains if branches for the cases
// that fail.
return new goog.json.Serializer(opt_replacer).serialize(object);
};
/**
* Class that is used to serialize JSON objects to a string.
* @param {?goog.json.Replacer=} opt_replacer Replacer.
* @constructor
*/
goog.json.Serializer = function(opt_replacer) {
'use strict';
/**
* @type {goog.json.Replacer|null|undefined}
* @private
*/
this.replacer_ = opt_replacer;
};
/**
* Serializes an object or a value to a JSON string.
*
* @param {*} object The object to serialize.
* @throws Error if there are loops in the object graph.
* @return {string} A JSON string representation of the input.
*/
goog.json.Serializer.prototype.serialize = function(object) {
'use strict';
const sb = [];
this.serializeInternal(object, sb);
return sb.join('');
};
/**
* Serializes a generic value to a JSON string
* @protected
* @param {*} object The object to serialize.
* @param {Array<string>} sb Array used as a string builder.
* @throws Error if there are loops in the object graph.
*/
goog.json.Serializer.prototype.serializeInternal = function(object, sb) {
'use strict';
if (object == null) {
// undefined == null so this branch covers undefined as well as null
sb.push('null');
return;
}
if (typeof object == 'object') {
if (Array.isArray(object)) {
this.serializeArray(object, sb);
return;
} else if (
object instanceof String || object instanceof Number ||
object instanceof Boolean) {
object = object.valueOf();
// Fall through to switch below.
} else {
this.serializeObject_(/** @type {!Object} */ (object), sb);
return;
}
}
switch (typeof object) {
case 'string':
this.serializeString_(object, sb);
break;
case 'number':
this.serializeNumber_(object, sb);
break;
case 'boolean':
sb.push(String(object));
break;
case 'function':
sb.push('null');
break;
default:
throw new Error('Unknown type: ' + typeof object);
}
};
/**
* Character mappings used internally for goog.string.quote
* @private
* @type {!Object}
*/
goog.json.Serializer.charToJsonCharCache_ = {
'\"': '\\"',
'\\': '\\\\',
'/': '\\/',
'\b': '\\b',
'\f': '\\f',
'\n': '\\n',
'\r': '\\r',
'\t': '\\t',
'\x0B': '\\u000b' // '\v' is not supported in JScript
};
/**
* Regular expression used to match characters that need to be replaced.
* The S60 browser has a bug where unicode characters are not matched by
* regular expressions. The condition below detects such behaviour and
* adjusts the regular expression accordingly.
* @private
* @type {!RegExp}
*/
goog.json.Serializer.charsToReplace_ = /\uffff/.test('\uffff') ?
/[\\\"\x00-\x1f\x7f-\uffff]/g :
/[\\\"\x00-\x1f\x7f-\xff]/g;
/**
* Serializes a string to a JSON string
* @private
* @param {string} s The string to serialize.
* @param {Array<string>} sb Array used as a string builder.
*/
goog.json.Serializer.prototype.serializeString_ = function(s, sb) {
'use strict';
// The official JSON implementation does not work with international
// characters.
sb.push('"', s.replace(goog.json.Serializer.charsToReplace_, function(c) {
'use strict';
// caching the result improves performance by a factor 2-3
let rv = goog.json.Serializer.charToJsonCharCache_[c];
if (!rv) {
rv = '\\u' + (c.charCodeAt(0) | 0x10000).toString(16).substr(1);
goog.json.Serializer.charToJsonCharCache_[c] = rv;
}
return rv;
}), '"');
};
/**
* Serializes a number to a JSON string
* @private
* @param {number} n The number to serialize.
* @param {Array<string>} sb Array used as a string builder.
*/
goog.json.Serializer.prototype.serializeNumber_ = function(n, sb) {
'use strict';
sb.push(isFinite(n) && !isNaN(n) ? String(n) : 'null');
};
/**
* Serializes an array to a JSON string
* @param {Array<string>} arr The array to serialize.
* @param {Array<string>} sb Array used as a string builder.
* @protected
*/
goog.json.Serializer.prototype.serializeArray = function(arr, sb) {
'use strict';
const l = arr.length;
sb.push('[');
let sep = '';
for (let i = 0; i < l; i++) {
sb.push(sep);
const value = arr[i];
this.serializeInternal(
this.replacer_ ? this.replacer_.call(arr, String(i), value) : value,
sb);
sep = ',';
}
sb.push(']');
};
/**
* Serializes an object to a JSON string
* @private
* @param {!Object} obj The object to serialize.
* @param {Array<string>} sb Array used as a string builder.
*/
goog.json.Serializer.prototype.serializeObject_ = function(obj, sb) {
'use strict';
sb.push('{');
let sep = '';
for (const key in obj) {
if (Object.prototype.hasOwnProperty.call(obj, key)) {
const value = obj[key];
// Skip functions.
if (typeof value != 'function') {
sb.push(sep);
this.serializeString_(key, sb);
sb.push(':');
this.serializeInternal(
this.replacer_ ? this.replacer_.call(obj, key, value) : value, sb);
sep = ',';
}
}
}
sb.push('}');
};
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