generate.md

Serialization AST to CSS

generate(ast[, options])

Generates a CSS string for given AST.

// generate with default settings
csstree.generate(ast);

// generate with options
csstree.generate(ast, {
    sourceMap: true
});

Options (optional):

• sourceMap
• decorator

sourceMap

Type: boolean
Default: false

Generates a source map (nodes should contain positions in loc property). Note, that an object instead of string is returned in that case.

import { parse, generate } from 'css-tree';

const ast = parse('.test { color: red }', {
    filename: 'my.css',
    positions: true
});

const result = generate(ast, { sourceMap: true });
// { css: '.test{color:red}', map: SourceMapGenerator {} }

decorator

Type: function
Default: none

A function that returns handlers used by a generator. TBD

mode

Type: "spec" or "safe"
Default: "spec"

CSS Syntax Module defines rules for CSS serialization that it must "round-trip" with parsing. The generator follows these rules and determines itself when to output the space to avoid unintended CSS tokens combining. However, some older browsers fail to parse the resulting CSS because they didn't follow the spec in some cases. For this reason, the generator supports two modes:

• safe (by default) which adds an extra space in some edge cases;
• spec which completely follows the spec.

import { parse, generate } from 'css-tree';

const ast = parse('a { border: calc(1px) solid #ff0000 }');

// safe mode is by default
// the same as console.log(generate(ast, { mode: 'safe' }));
console.log(generate(ast));
// a{border:calc(1px) solid#ff0000}

// spec mode
console.log(generate(ast, { mode: 'spec' }));
// a{border:calc(1px)solid#ff0000}