Function assertName

src/type/assertName.ts:19–39

(name: string)

 * ```
 */
export function assertName(name: string): string {
  if (name.length === 0) {
    throw new GraphQLError('Expected name to be a non-empty string.');
  }

  for (let i = 1; i < name.length; ++i) {
    if (!isNameContinue(name.charCodeAt(i))) {
      throw new GraphQLError(
        `Names must only contain [_a-zA-Z0-9] but "${name}" does not.`,
      );
    }
  }

  if (!isNameStart(name.charCodeAt(0))) {
    throw new GraphQLError(
      `Names must start with [_a-zA-Z] but "${name}" does not.`,
    );
  }

  return name;
}

/**
 * Upholds the spec rules about naming enum values.