Function parseNeverTrigger

packages/compiler/src/render3/r3_deferred_triggers.ts:64–89

(
  {expression, sourceSpan}: html.BlockParameter,
  triggers: t.DeferredBlockTriggers,
  errors: ParseError[],
)

/** Parses a `when` deferred trigger. */
export function parseNeverTrigger(
  {expression, sourceSpan}: html.BlockParameter,
  triggers: t.DeferredBlockTriggers,
  errors: ParseError[],
): void {
  const neverIndex = expression.indexOf('never');
  const neverSourceSpan = new ParseSourceSpan(
    sourceSpan.start.moveBy(neverIndex),
    sourceSpan.start.moveBy(neverIndex + 'never'.length),
  );
  const prefetchSpan = getPrefetchSpan(expression, sourceSpan);
  const hydrateSpan = getHydrateSpan(expression, sourceSpan);

  // This is here just to be safe, we shouldn't enter this function
  // in the first place if a block doesn't have the "on" keyword.
  if (neverIndex === -1) {
    errors.push(new ParseError(sourceSpan, `Could not find "never" keyword in expression`));
  } else {
    trackTrigger(
      'never',
      triggers,
      errors,
      new t.NeverDeferredTrigger(neverSourceSpan, sourceSpan, prefetchSpan, null, hydrateSpan),
    );
  }
}

/** Parses a `when` deferred trigger. */
export function parseWhenTrigger(