angular/angular-cli · warning

Invalid peer dependency ${peer} found in package.

Error message

Invalid peer dependency ${peer} found in package.

What it means

While validating a package's peerDependencies during `ng add`, the CLI resolves each peer range with `npa.resolve`. If the peer name/range string is malformed, npm-package-arg throws and this warning is emitted; that peer is skipped. The add proceeds without that peer check.

Source

Thrown at packages/angular/cli/src/commands/add/cli.ts:854

          );
        }
      }
    }

    return undefined;
  }

  private async getPeerDependencyConflicts(manifest: PackageManifest): Promise<string[] | false> {
    if (!manifest.peerDependencies) {
      return false;
    }

    const checks = Object.entries(manifest.peerDependencies).map(async ([peer, range]) => {
      let peerIdentifier;
      try {
        peerIdentifier = npa.resolve(peer, range);
      } catch {
        this.context.logger.warn(`Invalid peer dependency ${peer} found in package.`);

        return null;
      }

      if (peerIdentifier.type !== 'version' && peerIdentifier.type !== 'range') {
        // type === 'tag' | 'file' | 'directory' | 'remote' | 'git'
        // Cannot accurately compare these as the tag/location may have changed since install.
        return null;
      }

      try {
        const version = await this.findProjectVersion(peer);
        if (!version) {
          return null;
        }

        const options = { includePrerelease: true };
        if (

View on GitHub (pinned to bb72145f9a)

Solutions

1. Open the offending package's package.json and fix the malformed peerDependencies entry.
2. Pin to a version of the package that has valid peer metadata.
3. If the package is yours, validate the range with `npm-package-arg` before publishing.
4. Use `npm pkg get peerDependencies` to inspect quickly and correct the field.

Example fix

// before (invalid peer)
"peerDependencies": { "@angular/core": ">= >=16" }
// after
"peerDependencies": { "@angular/core": ">=16" }

try { npa.resolve(peer.name, peer.range); } catch { console.warn(`invalid peer: ${peer.name}`); }

function isValidPeerSpec(spec: unknown): spec is string { return typeof spec === 'string' && !!npa.tryResolve(spec); }

try { peerIdentifier = npa.resolve(peer, range); } catch { logger.warn(`Invalid peer dependency ${peer}`); return null; }

When it happens

Trigger: A dependency's package.json contains a peerDependencies entry with an invalid spec, e.g. a bad range like `">= <<"`, an empty range, or an unparseable name (git URL/alias syntax errors).

Common situations: Hand-edited or mis-published package.json; using an npm alias or prerelease tag syntax npm-package-arg cannot parse; typos in peer names in locally published/patched packages.

Related errors

• Could not parse package name from specifier: ${specifier}
• Invalid config found at ${workspace.filePath}. CLI should be
• Unable to fetch package information for '${context.packageId
• Invalid option key: '${key}'. Option keys must be alphanumer
• Incompatible peer dependencies found. See above for details.

AI-assisted analysis of angular/angular-cli@bb72145f9a (2026-08-30). Data as JSON: /api/errors/5f07a56576181c07. Report an issue: GitHub.