Const BUILTINS
BUILTINS: Map<string, function> = new Map<string, ShellBuiltin>([[`cd`, async ([target = homedir(), ...rest]: Array<string>, opts: ShellOptions, state: ShellState) => {const resolvedTarget = ppath.resolve(state.cwd, npath.toPortablePath(target));const stat = await xfs.statPromise(resolvedTarget);if (!stat.isDirectory()) {state.stderr.write(`cd: not a directory\n`);return 1;} else {state.cwd = resolvedTarget;return 0;}}],[`pwd`, async (args: Array<string>, opts: ShellOptions, state: ShellState) => {state.stdout.write(`${npath.fromPortablePath(state.cwd)}\n`);return 0;}],[`true`, async (args: Array<string>, opts: ShellOptions, state: ShellState) => {return 0;}],[`false`, async (args: Array<string>, opts: ShellOptions, state: ShellState) => {return 1;}],[`exit`, async ([code, ...rest]: Array<string>, opts: ShellOptions, state: ShellState) => {return state.exitCode = parseInt(code ?? state.variables[`?`], 10);}],[`echo`, async (args: Array<string>, opts: ShellOptions, state: ShellState) => {state.stdout.write(`${args.join(` `)}\n`);return 0;}],[`__ysh_run_procedure`, async (args: Array<string>, opts: ShellOptions, state: ShellState) => {const procedure = state.procedures[args[0]];const exitCode = await start(procedure, {stdin: new ProtectedStream<Readable>(state.stdin),stdout: new ProtectedStream<Writable>(state.stdout),stderr: new ProtectedStream<Writable>(state.stderr),}).run();return exitCode;}],[`__ysh_set_redirects`, async (args: Array<string>, opts: ShellOptions, state: ShellState) => {let stdin = state.stdin;let stdout = state.stdout;const stderr = state.stderr;const inputs: Array<() => Readable> = [];const outputs: Array<Writable> = [];let t = 0;while (args[t] !== `--`) {const type = args[t++];const count = Number(args[t++]);const last = t + count;for (let u = t; u < last; ++t, ++u) {switch (type) {case `<`: {inputs.push(() => {return xfs.createReadStream(ppath.resolve(state.cwd, npath.toPortablePath(args[u])));});} break;case `<<<`: {inputs.push(() => {const input = new PassThrough();process.nextTick(() => {input.write(`${args[u]}\n`);input.end();});return input;});} break;case `>`: {outputs.push(xfs.createWriteStream(ppath.resolve(state.cwd, npath.toPortablePath(args[u]))));} break;case `>>`: {outputs.push(xfs.createWriteStream(ppath.resolve(state.cwd, npath.toPortablePath(args[u])), {flags: `a`}));} break;}}}if (inputs.length > 0) {const pipe = new PassThrough();stdin = pipe;const bindInput = (n: number) => {if (n === inputs.length) {pipe.end();} else {const input = inputs[n]();input.pipe(pipe, {end: false});input.on(`end`, () => {bindInput(n + 1);});}};bindInput(0);}if (outputs.length > 0) {const pipe = new PassThrough();stdout = pipe;for (const output of outputs) {pipe.pipe(output);}}const exitCode = await start(makeCommandAction(args.slice(t + 1), opts, state), {stdin: new ProtectedStream<Readable>(stdin),stdout: new ProtectedStream<Writable>(stdout),stderr: new ProtectedStream<Writable>(stderr),}).run();// Close all the outputs (since the shell never closes the output stream)await Promise.all(outputs.map(output => {// Wait until the output got flushed to the diskreturn new Promise(resolve => {output.on(`close`, () => {resolve();});output.end();});}));return exitCode;}],])
@yarnpkg/shellA JavaScript implementation of a bash-like shell (we use it in Yarn 2 to provide cross-platform scripting). This package exposes an API that abstracts both the parser and the interpreter; should you only need the parser you can check out
@yarnpkg/parsers, but you probably won't need it.Usage
import {execute} from '@yarnpkg/shell';process.exitCode = await execute(
ls "$1" | wc -l, [process.cwd()]);Features
ls *.txt)Help Wanted
mv build/{index.js,index.build.js},echo {foo,bar},FOO=a,b echo {$FOO,x})Non-Goals