@netlify/config/src/normalize.js

Netlify config module

import { normalizeFunctionsProps, WILDCARD_ALL } from './functions_config.js'
import { mergeConfigs } from './merge.js'
import { DEFAULT_ORIGIN } from './origin.js'
import { removeFalsy } from './utils/remove_falsy.js'

// Normalize configuration object
export const normalizeConfig = function (config) {
  const configA = removeEmpty(config)
  const { build, functions, plugins, ...configB } = mergeConfigs([DEFAULT_CONFIG, configA])
  const { build: buildA, functions: functionsA, functionsDirectoryProps } = normalizeFunctionsProps(build, functions)
  const pluginsA = plugins.map(normalizePlugin)
  return { ...configB, build: buildA, functions: functionsA, plugins: pluginsA, ...functionsDirectoryProps }
}

// Remove empty strings.
// This notably ensures that empty strings in the build command are removed.
// Otherwise those would be run during builds, making the build fail.
const removeEmpty = function ({ build, ...config }) {
  return removeFalsy({ ...config, build: removeFalsy(build) })
}

const DEFAULT_CONFIG = {
  build: {
    environment: {},
    publish: '.',
    publishOrigin: DEFAULT_ORIGIN,
    processing: { css: {}, html: {}, images: {}, js: {} },
    services: {},
  },
  functions: { [WILDCARD_ALL]: {} },
  plugins: [],
}

const normalizePlugin = function ({ inputs = {}, ...plugin }) {
  return removeFalsy({ ...plugin, inputs })
}