angular/angular-cli · error · Error

Target name already exists.

Error message

Target name already exists.

What it means

TargetDefinitionCollection.add() enforces unique target names within a project. If a target with the same name is already registered (checked via has(name)) it throws before validating/creating the target. Duplicate target names would make the 'project:target' selector ambiguous.

Source

Thrown at packages/angular_devkit/core/src/workspace/definitions.ts:222

    }
  }
}

export class TargetDefinitionCollection extends DefinitionCollection<TargetDefinition> {
  constructor(
    initial?: Record<string, TargetDefinition>,
    listener?: DefinitionCollectionListener<TargetDefinition>,
  ) {
    super(initial, listener);
  }

  add(
    definition: {
      name: string;
    } & TargetDefinition,
  ): TargetDefinition {
    if (this.has(definition.name)) {
      throw new Error('Target name already exists.');
    }
    this._validateName(definition.name);

    const target = {
      builder: definition.builder,
      options: definition.options,
      configurations: definition.configurations,
      defaultConfiguration: definition.defaultConfiguration,
    };

    super.set(definition.name, target);

    return target;
  }

  override set(name: string, value: TargetDefinition): this {
    this._validateName(name);

View on GitHub (pinned to bb72145f9a)

Solutions

1. Check project targets (has) before adding and skip or update the existing target.
2. Use set() on the target collection if overwriting is intended.
3. Remove the existing target first, then add the new one.

Example fix

// before
project.addTarget({ name: 'build', builder: '@angular-devkit/build-angular:browser' });
// after
if (!project.targets.has('build')) {
  project.addTarget({ name: 'build', builder: '@angular-devkit/build-angular:browser' });
}

if (project.targets.has(targetName)) {
  // skip or update instead of adding
} else {
  project.addTarget({ name: targetName, builder, options });
}

function canAddTarget(project: ProjectDefinition, name: string): boolean {
  return typeof name === 'string' && !project.targets.has(name);
}

try {
  project.addTarget({ name, builder });
} catch (e) {
  if (e.message === 'Target name already exists.') {
    project.targets.set(name, { builder, options }); // overwrite intentionally
  } else throw e;
}

When it happens

Trigger: Calling project.addTarget({ name: 'build', builder: '...' }) when a 'build' target already exists on that project.

Common situations: Schematic re-run adding standard targets (build, serve, test) twice; scripts that merge configurations from two sources; applying the same generator to a project twice.

Related errors

• Project name already exists.
• Target name must be a string.
• "${name}" must be a JSON value.
• Project name must be a valid npm package name.
• Unable to read workspace file.

AI-assisted analysis of angular/angular-cli@bb72145f9a (2026-08-30). Data as JSON: /api/errors/909337638faf663a. Report an issue: GitHub.