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<article name="Compatibility"
        link="/en/docs/njs/compatibility.html"
        lang="en"
        rev="1">

<section>

<para>
njs is created in compliance with
<link url="http://www.ecma-international.org/ecma-262/5.1/">ECMAScript 5.1</link>
(strict mode) with some
<link url="http://www.ecma-international.org/ecma-262/6.0/">ECMAScript 6</link>
and later extensions.
The compliance is still evolving.
</para>

</section>


<section id="supported" name="What is currently supported">

<para>
<list type="bullet">

<listitem>
Boolean values, numbers, strings, objects, arrays,
functions, and regular expressions
</listitem>

<listitem>
ES5.1 operators, ES7 exponentiation operators
</listitem>

<listitem>
ES5.1 statements: <literal>var</literal>, <literal>if</literal>,
<literal>else</literal>, <literal>switch</literal>, <literal>for</literal>,
<literal>for in</literal>, <literal>while</literal>,
<literal>do while</literal>, <literal>break</literal>,
<literal>continue</literal>, <literal>return</literal>, <literal>try</literal>,
<literal>catch</literal>, <literal>throw</literal>, <literal>finally</literal>
</listitem>

<listitem>
ES6 <literal>Number</literal> and
<literal>Math</literal> properties and methods
</listitem>

<listitem>
<literal>String</literal> methods:
<list type="bullet">

<listitem>
ES5.1:
<literal>fromCharCode</literal>, <literal>concat</literal>,
<literal>slice</literal>, <literal>substring</literal>,
<literal>substr</literal>, <literal>charAt</literal>,
<literal>charCodeAt</literal>, <literal>indexOf</literal>,
<literal>lastIndexOf</literal>, <literal>toLowerCase</literal>,
<literal>toUpperCase</literal>, <literal>trim</literal>,
<literal>search</literal>, <literal>match</literal>, <literal>split</literal>,
<literal>replace</literal>
</listitem>

<listitem>
ES6:
<literal>fromCodePoint</literal>, <literal>codePointAt</literal>,
<literal>includes</literal>, <literal>startsWith</literal>,
<literal>endsWith</literal>, <literal>repeat</literal>
</listitem>

<listitem>
non-standard:
<literal>bytesFrom</literal> (0.2.3)
<literal>fromUTF8</literal>, <literal>toUTF8</literal>,
<literal>fromBytes</literal>, <literal>toBytes</literal>
</listitem>
</list>

</listitem>

<listitem>
<literal>Object</literal> methods:
<list type="bullet">
<listitem>
ES5.1:
<literal>create</literal> (support without properties list),
<literal>keys</literal>,
<literal>defineProperty</literal>,
<literal>defineProperties</literal>,
<literal>getOwnPropertyDescriptor</literal>,
<literal>getPrototypeOf</literal>,
<literal>hasOwnProperty</literal>,
<literal>isPrototypeOf</literal>,
<literal>preventExtensions</literal>,
<literal>isExtensible</literal>,
<literal>freeze</literal>,
<literal>isFrozen</literal>,
<literal>seal</literal>,
<literal>isSealed</literal>
</listitem>
</list>

</listitem>

<listitem>
<literal>Array</literal> methods:
<list type="bullet">
<listitem>
ES5.1:
<literal>isArray</literal>, <literal>slice</literal>, <literal>splice</literal>,
<literal>push</literal>, <literal>pop</literal>, <literal>unshift</literal>,
<literal>shift</literal>, <literal>reverse</literal>, <literal>sort</literal>,
<literal>join</literal>, <literal>concat</literal>, <literal>indexOf</literal>,
<literal>lastIndexOf</literal>, <literal>forEach</literal>,
<literal>some</literal>, <literal>every</literal>, <literal>filter</literal>,
<literal>map</literal>, <literal>reduce</literal>,
<literal>reduceRight</literal>
</listitem>

<listitem>
ES6:
<literal>of</literal>, <literal>fill</literal>, <literal>find</literal>,
<literal>findIndex</literal>
</listitem>

<listitem>
ES7: <literal>includes</literal>
</listitem>
</list>

</listitem>

<listitem>
ES5.1 <literal>Function</literal> methods:
<literal>call</literal>, <literal>apply</literal>, <literal>bind</literal>
</listitem>

<listitem>
ES5.1 <literal>RegExp</literal> methods:
<literal>test</literal>, <literal>exec</literal>
</listitem>

<listitem>
ES5.1 <literal>Date</literal> methods
</listitem>

<listitem>
ES5.1 <literal>JSON</literal> object
</listitem>

<listitem>
ES5.1 global functions:
<literal>isFinite</literal>, <literal>isNaN</literal>,
<literal>parseFloat</literal>, <literal>parseInt</literal>,
<literal>decodeURI</literal>, <literal>decodeURIComponent</literal>,
<literal>encodeURI</literal>, <literal>encodeURIComponent</literal>
</listitem>

<listitem>
<literal>Error</literal> objects:
<literal>Error</literal>, <literal>EvalError</literal>,
<literal>InternalError</literal>, <literal>RangeError</literal>,
<literal>ReferenceError</literal>, <literal>SyntaxError</literal>,
<literal>TypeError</literal>, <literal>URIError</literal>
</listitem>

<listitem>
<literal>setTimeout()</literal> and <literal>clearTimeout()</literal> functions
(0.2.0)
</listitem>

<listitem>
<link url="https://nodejs.org/api/fs.html#fs_file_system">Node.js style</link>
<literal>File system</literal> methods:
<literal>fs.readFile</literal>, <literal>fs.readFileSync</literal>,
<literal>fs.appendFile</literal>, <literal>fs.appendFileSync</literal>,
<literal>fs.writeFile</literal>, <literal>fs.writeFileSync</literal>
</listitem>

<listitem>
<link url="https://nodejs.org/api/crypto.html#crypto_class_hash">Node.js style</link>
<literal>Crypto</literal> methods (0.2.0):
<literal>crypto.createHash</literal>,
<literal>crypto.createHmac</literal>

</listitem>

</list>
</para>

</section>


<section id="not_supported" name="What is not supported yet">

<para>
<list type="bullet">

<listitem>
ES6 <literal>let</literal> and <literal>const</literal> declarations
</listitem>

<listitem>
labels
</listitem>

<listitem>
<literal>arguments</literal> array
</listitem>

<listitem>
<literal>eval</literal> function
</listitem>

<listitem>
<literal>new Function()</literal> constructor
</listitem>

<listitem>
<literal>setInterval</literal>,
<literal>setImmediate</literal> functions
</listitem>

<listitem>
non-integer fractions (<literal>.235</literal>)
</listitem>

</list>
</para>

</section>

</article>