@netlify/config/lib/build_dir.js

Netlify config module

import { isDirectory } from 'path-type';
import { throwUserError } from './error.js';
/**
 * Retrieve the build directory used to resolve most paths.
 * This is (in priority order):
 *  - `build.base`
 *  - `--repositoryRoot`
 *  - the current directory (default value of `--repositoryRoot`)
 */
export const getBuildDir = async function (repositoryRoot, base) {
    const buildDir = base === undefined ? repositoryRoot : base;
    await checkBuildDir(buildDir, repositoryRoot);
    return buildDir;
};
/**
 * The build directory is used as the current directory of build commands and
 * build plugins. Therefore, it must exist.
 * We already check `repositoryRoot` earlier in the code, so only need to check
 * `buildDir` when it is the base directory instead.
 */
const checkBuildDir = async function (buildDir, repositoryRoot) {
    if (buildDir === repositoryRoot || (await isDirectory(buildDir))) {
        return;
    }
    throwUserError(`Base directory does not exist: ${buildDir}`);
};