Function getSupportedNodeVersion

packages/build-utils/src/fs/node-version.ts:128–198

(
  engineRange: string | undefined,
  isAuto = false,
  availableVersions?: NodeVersionMajor[]
)

}

export async function getSupportedNodeVersion(
  engineRange: string | undefined,
  isAuto = false,
  availableVersions?: NodeVersionMajor[]
): Promise<NodeVersion> {
  let selection: NodeVersion | undefined;

  if (engineRange) {
    const found =
      validRange(engineRange) &&
      getOptions().some(o => {
        // the array is already in order so return the first
        // match which will be the newest version of node
        selection = o;
        return (
          intersects(o.range, engineRange) &&
          (availableVersions?.length
            ? availableVersions.includes(o.major)
            : true)
        );
      });
    if (!found) {
      throw new NowBuildError({
        code: 'BUILD_UTILS_NODE_VERSION_INVALID',
        link: 'https://vercel.link/node-version',
        message: `Found invalid or discontinued Node.js Version: "${engineRange}". ${getHint(
          isAuto,
          availableVersions
        )}`,
      });
    }
  }

  if (!selection) {
    selection = getLatestNodeVersion(availableVersions);
  }

  if (selection.state === 'discontinued') {
    const intro = `Node.js Version "${selection.range}" is discontinued and must be upgraded.`;
    throw new NowBuildError({
      code: 'BUILD_UTILS_NODE_VERSION_DISCONTINUED',
      link: 'https://vercel.link/node-version',
      message: `${intro} ${getHint(isAuto)}`,
    });
  }

  debug(`Selected Node.js ${selection.range}`);

  if (selection.state === 'deprecated') {
    const d = selection.formattedDate;
    // formattedDate should never be undefined because the check for deprecated
    // expects that discontinueDate is set but this check is done for completeness
    if (d) {
      console.warn(
        `Error: Node.js version ${
          selection.range
        } is deprecated. Deployments created on or after ${d} will fail to build. ${getHint(
          isAuto