@netlify/build/lib/plugins/child/typescript.js

Netlify build module

import { extname } from 'path';
import { register } from 'ts-node';
import { addErrorInfo } from '../../error/info.js';
// Allow local plugins to be written with TypeScript.
// Local plugins cannot be transpiled by the build command since they can be run
// before it. Therefore, we type-check and transpile them automatically using
// `ts-node`.
export const registerTypeScript = function (pluginPath) {
    if (!isTypeScriptPlugin(pluginPath)) {
        return;
    }
    return register();
};
// On TypeScript errors, adds information about the `ts-node` configuration,
// which includes the resolved `tsconfig.json`.
export const addTsErrorInfo = function (error, tsNodeService) {
    if (tsNodeService === undefined) {
        return;
    }
    const { config: { raw: { compilerOptions }, }, options: realTsNodeOptions, } = tsNodeService;
    // filter out functions as they cannot be serialized
    const tsNodeOptions = Object.fromEntries(Object.entries(realTsNodeOptions).filter(([, val]) => typeof val !== 'function'));
    addErrorInfo(error, { tsConfig: { compilerOptions, tsNodeOptions } });
};
const isTypeScriptPlugin = function (pluginPath) {
    return TYPESCRIPT_EXTENSIONS.has(extname(pluginPath));
};
const TYPESCRIPT_EXTENSIONS = new Set(['.ts', '.tsx', '.mts', '.cts']);