<!doctype html> <html lang="en"> <head> <meta charset="utf-8"> <title>Query String | Node.js v6.17.1 Documentation</title> <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato:400,700,400italic"> <link rel="stylesheet" href="assets/style.css"> <link rel="stylesheet" href="assets/sh.css"> <link rel="canonical" href="https://nodejs.org/api/querystring.html"> </head> <body class="alt apidoc" id="api-section-querystring"> <div id="content" class="clearfix"> <div id="column2" class="interior"> <div id="intro" class="interior"> <a href="/" title="Go back to the home page"> Node.js </a> </div> <ul> <li><a class="nav-documentation" href="documentation.html">About these Docs</a></li> <li><a class="nav-synopsis" href="synopsis.html">Usage & Example</a></li> </ul> <div class="line"></div> <ul> <li><a class="nav-assert" href="assert.html">Assertion Testing</a></li> <li><a class="nav-buffer" href="buffer.html">Buffer</a></li> <li><a class="nav-addons" href="addons.html">C++ Addons</a></li> <li><a class="nav-n-api" href="n-api.html">C/C++ Addons - 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Stable</div><!--name=querystring--> <p>The <code>querystring</code> module provides utilities for parsing and formatting URL query strings. It can be accessed using:</p> <pre><code class="lang-js">const querystring = require('querystring'); </code></pre> <h2>querystring.escape(str)<span><a class="mark" href="#querystring_querystring_escape_str"id="querystring_querystring_escape_str">#</a></span></h2> <div class="api_metadata"> <span>Added in: v0.1.25</span> </div><ul> <li><code>str</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> </ul> <p>The <code>querystring.escape()</code> method performs URL percent-encoding on the given <code>str</code> in a manner that is optimized for the specific requirements of URL query strings.</p> <p>The <code>querystring.escape()</code> method is used by <code>querystring.stringify()</code> and is generally not expected to be used directly. It is exported primarily to allow application code to provide a replacement percent-encoding implementation if necessary by assigning <code>querystring.escape</code> to an alternative function.</p> <h2>querystring.parse(str[, sep[, eq[, options]]])<span><a class="mark" href="#querystring_querystring_parse_str_sep_eq_options"id="querystring_querystring_parse_str_sep_eq_options">#</a></span></h2> <div class="api_metadata"> <span>Added in: v0.1.25</span> </div><ul> <li><code>str</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The URL query string to parse</li> <li><code>sep</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The substring used to delimit key and value pairs in the query string. Defaults to <code>'&'</code>.</li> <li><code>eq</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a>. The substring used to delimit keys and values in the query string. Defaults to <code>'='</code>.</li> <li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a><ul> <li><code>decodeURIComponent</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> The function to use when decoding percent-encoded characters in the query string. Defaults to <code>querystring.unescape()</code>.</li> <li><code>maxKeys</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Specifies the maximum number of keys to parse. Defaults to <code>1000</code>. Specify <code>0</code> to remove key counting limitations.</li> </ul> </li> </ul> <p>The <code>querystring.parse()</code> method parses a URL query string (<code>str</code>) into a collection of key and value pairs.</p> <p>For example, the query string <code>'foo=bar&abc=xyz&abc=123'</code> is parsed into:</p> <!-- eslint-skip --> <pre><code class="lang-js">{ foo: 'bar', abc: ['xyz', '123'] } </code></pre> <p><em>Note</em>: The object returned by the <code>querystring.parse()</code> method <em>does not</em> prototypically extend from the JavaScript <code>Object</code>. This means that the typical <code>Object</code> methods such as <code>obj.toString()</code>, <code>obj.hasOwnProperty()</code>, and others are not defined and <em>will not work</em>.</p> <p>By default, percent-encoded characters within the query string will be assumed to use UTF-8 encoding. If an alternative character encoding is used, then an alternative <code>decodeURIComponent</code> option will need to be specified as illustrated in the following example:</p> <pre><code class="lang-js">// Assuming gbkDecodeURIComponent function already exists... querystring.parse('w=%D6%D0%CE%C4&foo=bar', null, null, { decodeURIComponent: gbkDecodeURIComponent }); </code></pre> <h2>querystring.stringify(obj[, sep[, eq[, options]]])<span><a class="mark" href="#querystring_querystring_stringify_obj_sep_eq_options"id="querystring_querystring_stringify_obj_sep_eq_options">#</a></span></h2> <div class="api_metadata"> <span>Added in: v0.1.25</span> </div><ul> <li><code>obj</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> The object to serialize into a URL query string</li> <li><code>sep</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> The substring used to delimit key and value pairs in the query string. Defaults to <code>'&'</code>.</li> <li><code>eq</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a>. The substring used to delimit keys and values in the query string. Defaults to <code>'='</code>.</li> <li><code>options</code><ul> <li><code>encodeURIComponent</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> The function to use when converting URL-unsafe characters to percent-encoding in the query string. Defaults to <code>querystring.escape()</code>.</li> </ul> </li> </ul> <p>The <code>querystring.stringify()</code> method produces a URL query string from a given <code>obj</code> by iterating through the object's "own properties".</p> <p>It serializes the following types of values passed in <code>obj</code>: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean[]></a> Any other input values will be coerced to empty strings.</p> <p>For example:</p> <pre><code class="lang-js">querystring.stringify({ foo: 'bar', baz: ['qux', 'quux'], corge: '' }); // returns 'foo=bar&baz=qux&baz=quux&corge=' querystring.stringify({ foo: 'bar', baz: 'qux' }, ';', ':'); // returns 'foo:bar;baz:qux' </code></pre> <p>By default, characters requiring percent-encoding within the query string will be encoded as UTF-8. If an alternative encoding is required, then an alternative <code>encodeURIComponent</code> option will need to be specified as illustrated in the following example:</p> <pre><code class="lang-js">// Assuming gbkEncodeURIComponent function already exists, querystring.stringify({ w: '中文', foo: 'bar' }, null, null, { encodeURIComponent: gbkEncodeURIComponent }); </code></pre> <h2>querystring.unescape(str)<span><a class="mark" href="#querystring_querystring_unescape_str"id="querystring_querystring_unescape_str">#</a></span></h2> <div class="api_metadata"> <span>Added in: v0.1.25</span> </div><ul> <li><code>str</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> </ul> <p>The <code>querystring.unescape()</code> method performs decoding of URL percent-encoded characters on the given <code>str</code>.</p> <p>The <code>querystring.unescape()</code> method is used by <code>querystring.parse()</code> and is generally not expected to be used directly. It is exported primarily to allow application code to provide a replacement decoding implementation if necessary by assigning <code>querystring.unescape</code> to an alternative function.</p> <p>By default, the <code>querystring.unescape()</code> method will attempt to use the JavaScript built-in <code>decodeURIComponent()</code> method to decode. If that fails, a safer equivalent that does not throw on malformed URLs will be used.</p> </div> </div> </div> <script src="assets/sh_main.js"></script> <script src="assets/sh_javascript.min.js"></script> <script>highlight(undefined, undefined, 'pre');</script> <!-- __TRACKING__ --> </body> </html>