@swc/core

These are the core SWC APIs mainly useful for build tool authors.

transform

@swc/core provides appropriate .d.ts file, so you may not need this. Returns Promise<{ code: string, map?: string }>

const swc = require("@swc/core");

swc
  .transform("source code", {
    // Some options cannot be specified in .swcrc
    filename: "input.js",
    sourceMaps: true,
    // Input files are treated as module by default.
    isModule: false,

    // All options below can be configured via .swcrc
    jsc: {
      parser: {
        syntax: "ecmascript",
      },
      transform: {},
    },
  })
  .then((output) => {
    output.code; // transformed code
    output.map; // source map (in string)
  });

transformSync

Returns { code: string, map?: string }

transformFile

Returns Promise<{ code: string, map?: string }>

transformFileSync

Returns { code: string, map?: string }

parse

Returns Promise<Script | Module>

const swc = require('@swc/core')

swc
  .parse("source code", {
    syntax: "ecmascript", // "ecmascript" | "typesscript"
    comments: false,
    script: true,

    // Defaults to es3
    target: "es3",

    // Input source code are treated as module by default
    isModule: false,
  })
  .then((module) => {
    module.type // file type
    module.body; // AST
  })

Type Declarations

export declare function parse(src: string, options: ParseOptions & {
    isModule: false;
}): Promise<Script>;
export declare function parse(src: string, options?: ParseOptions): Promise<Module>;
export declare function parseSync(src: string, options: ParseOptions & {
    isModule: false;
}): Script;
export declare function parseSync(src: string, options?: ParseOptions): Module;
export declare function parseFile(path: string, options: ParseOptions & {
    isModule: false;
}): Promise<Script>;
export declare function parseFile(path: string, options?: ParseOptions): Promise<Module>;
export declare function parseFileSync(path: string, options: ParseOptions & {
    isModule: false;
}): Script;
export declare function parseFileSync(path: string, options?: ParseOptions): Module;

export interface Module extends Node, HasSpan, HasInterpreter {
    type: "Module";
    body: ModuleItem[];
}
export interface Script extends Node, HasSpan, HasInterpreter {
    type: "Script";
    body: Statement[];
}
export declare type ParseOptions = ParserConfig & {
  comments?: boolean;
  script?: boolean;
  /**
   * Defaults to es3.
   */
  target?: JscTarget;
};
export declare type JscTarget = "es3" | "es5" | "es2015" | "es2016" | "es2017" | "es2018" | "es2019" | "es2020" | "es2021" | "es2022";
export declare type ParserConfig = TsParserConfig | EsParserConfig;
export interface TsParserConfig {
    syntax: "typescript";
    /**
     * Defaults to `false`.
     */
    tsx?: boolean;
    /**
     * Defaults to `false`.
     */
    decorators?: boolean;
    /**
     * Defaults to `false`
     */
    dynamicImport?: boolean;
}
export interface EsParserConfig {
    syntax: "ecmascript";
    /**
     * Defaults to false.
     */
    jsx?: boolean;
    /**
     * Defaults to `false`
     */
    functionBind?: boolean;
    /**
     * Defaults to `false`
     */
    decorators?: boolean;
    /**
     * Defaults to `false`
     */
    decoratorsBeforeExport?: boolean;
    /**
     * Defaults to `false`
     */
    exportDefaultFrom?: boolean;
    /**
     * Defaults to `false`
     */
    importAssertions?: boolean;
}

parseSync

Returns Script | Module

parseFile

Returns Promise<Script | Module>

parseFileSync

Returns Script | Module

minify

Returns Promise<Output>

const swc = require('@swc/core')

swc
  .minify('source code', opts?: JsMinifyOptions)
  .then(output => {
    output.code // transformed code
    output.map // sourcemap (in string)
  })

Type Declarations

export declare function minify(src: string, opts?: JsMinifyOptions): Promise<Output>;
export declare function minifySync(src: string, opts?: JsMinifyOptions): Output;

export interface Output {
    code: string;
    map?: string;
}
export declare type TerserEcmaVersion = 5 | 2015 | 2016 | string | number;
export interface JsMinifyOptions {
    compress?: TerserCompressOptions | boolean;
    mangle?: TerserMangleOptions | boolean;
    ecma?: TerserEcmaVersion;
    keep_classnames?: boolean;
    keep_fnames?: boolean;
    module?: boolean;
    safari10?: boolean;
    toplevel?: boolean;
    sourceMap?: boolean;
    outputPath?: string;
    inlineSourcesContent?: boolean;
}
export interface TerserCompressOptions {
    arguments?: boolean;
    arrows?: boolean;
    booleans?: boolean;
    booleans_as_integers?: boolean;
    collapse_vars?: boolean;
    comparisons?: boolean;
    computed_props?: boolean;
    conditionals?: boolean;
    dead_code?: boolean;
    defaults?: boolean;
    directives?: boolean;
    drop_console?: boolean;
    drop_debugger?: boolean;
    ecma?: TerserEcmaVersion;
    evaluate?: boolean;
    expression?: boolean;
    global_defs?: any;
    hoist_funs?: boolean;
    hoist_props?: boolean;
    hoist_vars?: boolean;
    ie8?: boolean;
    if_return?: boolean;
    inline?: 0 | 1 | 2 | 3;
    join_vars?: boolean;
    keep_classnames?: boolean;
    keep_fargs?: boolean;
    keep_fnames?: boolean;
    keep_infinity?: boolean;
    loops?: boolean;
    negate_iife?: boolean;
    passes?: number;
    properties?: boolean;
    pure_getters?: any;
    pure_funcs?: string[];
    reduce_funcs?: boolean;
    reduce_vars?: boolean;
    sequences?: any;
    side_effects?: boolean;
    switches?: boolean;
    top_retain?: any;
    toplevel?: any;
    typeofs?: boolean;
    unsafe_passes?: boolean;
    unsafe_arrows?: boolean;
    unsafe_comps?: boolean;
    unsafe_function?: boolean;
    unsafe_math?: boolean;
    unsafe_symbols?: boolean;
    unsafe_methods?: boolean;
    unsafe_proto?: boolean;
    unsafe_regexp?: boolean;
    unsafe_undefined?: boolean;
    unused?: boolean;
    module?: boolean;
}
export interface TerserMangleOptions {
    props?: TerserManglePropertiesOptions;
    top_level?: boolean;
    keep_class_names?: boolean;
    keep_fn_names?: boolean;
    keep_private_props?: boolean;
    ie8?: boolean;
    safari10?: boolean;
    reserved?: string[];
}
export interface TerserManglePropertiesOptions {
}

minifySync

Returns Output

Options

This still needs to be documented. Contributions welcome!