angular__angular/tools/release/version-name/parse-version.ts

/** Regular expression that matches version names and the individual version segments. */
const versionNameRegex = /^(\d+)\.(\d+)\.(\d+)(?:-(alpha|beta|rc)\.(\d)+)?$/;

export class Version {

  constructor(
    /** Major version number */
    public major: number,
    /** Minor version number */
    public minor: number,
    /** Patch version number */
    public patch: number,
    /** Pre-release label for the version (e.g. alpha, beta, rc) */
    public prereleaseLabel?: string,
    /** Number for the pre-release. There can be multiple pre-releases for a version. */
    public prereleaseNumber?: number) {}

  /** Serializes the version info into a string formatted version name. */
  format(): string {
    return serializeVersion(this);
  }

  clone(): Version {
    return new Version(this.major, this.minor, this.patch, this.prereleaseLabel,
      this.prereleaseNumber);
  }
}

/**
 * Parses the specified version and returns an object that represents the individual
 * version segments.
 */
export function parseVersionName(version: string): Version | null {
  const matches = version.match(versionNameRegex);

  if (!matches) {
    return null;
  }

  return new Version(
    Number(matches[1]),
    Number(matches[2]),
    Number(matches[3]),
    matches[4],
    Number(matches[5]));
}

/** Serializes the specified version into a string. */
export function serializeVersion(newVersion: Version): string {
  const {major, minor, patch, prereleaseLabel, prereleaseNumber} = newVersion;

  let versionString = `${major}.${minor}.${patch}`;

  if (prereleaseLabel && prereleaseNumber) {
    versionString += `-${prereleaseLabel}.${prereleaseNumber}`;
  }

  return versionString;
}