Function addDependency

packages/schematics/angular/utility/dependency.ts:141–228

(
  name: string,
  specifier: string,
  options: {
    /**
     * The type of the dependency determines the section of the `package.json` to which the
     * dependency will be added. Defaults to {@link DependencyType.Default} (`dependencies`).
     */
    type?: DependencyType;

    /**
     * The path of the package manifest file (`package.json`) that will be modified.
     * Defaults to `/package.json`.
     */
    packageJsonPath?: string;

    /**
     * The dependency installation behavior to use to determine whether a
     * {@link NodePackageInstallTask} should be scheduled after adding the dependency.
     * Defaults to {@link InstallBehavior.Auto}.
     */
    install?: InstallBehavior;

    /**
     * The behavior to use when the dependency already exists within the `package.json`.
     * Defaults to {@link ExistingBehavior.Replace}.
     */
    existing?: ExistingBehavior;
  } = {},
)

 * @returns A Schematics {@link Rule}
 */
export function addDependency(
  name: string,
  specifier: string,
  options: {
    /**
     * The type of the dependency determines the section of the `package.json` to which the
     * dependency will be added. Defaults to {@link DependencyType.Default} (`dependencies`).
     */
    type?: DependencyType;

    /**
     * The path of the package manifest file (`package.json`) that will be modified.
     * Defaults to `/package.json`.
     */
    packageJsonPath?: string;

    /**
     * The dependency installation behavior to use to determine whether a
     * {@link NodePackageInstallTask} should be scheduled after adding the dependency.
     * Defaults to {@link InstallBehavior.Auto}.
     */
    install?: InstallBehavior;

    /**
     * The behavior to use when the dependency already exists within the `package.json`.
     * Defaults to {@link ExistingBehavior.Replace}.
     */
    existing?: ExistingBehavior;
  } = {},
): Rule {
  const {
    type = DependencyType.Default,
    packageJsonPath = '/package.json',
    install = InstallBehavior.Auto,
    existing = ExistingBehavior.Replace,
  } = options;

  return (tree, context) => {
    const manifest = tree.readJson(packageJsonPath) as MinimalPackageManifest;
    const dependencySection = manifest[type];

    if (!dependencySection) {
      // Section is not present. The dependency can be added to a new object literal for the section.
      manifest[type] = { [name]: specifier };
    } else {
      const existingSpecifier = dependencySection[name];

      if (existingSpecifier === specifier) {
        // Already present with same specifier
        return;
      }

      if (existingSpecifier) {
        // Already present but different specifier

        if (existing === ExistingBehavior.Skip) {
          return;
        }