function isOptionalDependency()

in packages/metro/src/ModuleGraph/worker/collectDependencies.js [364:404]

32 lines of code
11 McCabe index (conditional complexity)


function isOptionalDependency<TSplitCondition>(
  name: string,
  path: NodePath<>,
  state: State<TSplitCondition>,
): boolean {
  const {allowOptionalDependencies} = state;

  // The async require module is a 'built-in'. Resolving should never fail -> treat it as non-optional.
  if (name === state.asyncRequireModulePathStringLiteral?.value) {
    return false;
  }

  const isExcluded = () =>
    Array.isArray(allowOptionalDependencies.exclude) &&
    allowOptionalDependencies.exclude.includes(name);

  if (!allowOptionalDependencies || isExcluded()) {
    return false;
  }

  // Valid statement stack for single-level try-block: expressionStatement -> blockStatement -> tryStatement
  let sCount = 0;
  let p = path;
  while (p && sCount < 3) {
    if (p.isStatement()) {
      if (p.node.type === 'BlockStatement') {
        // A single-level should have the tryStatement immediately followed BlockStatement
        // with the key 'block' to distinguish from the finally block, which has key = 'finalizer'
        return (
          p.parentPath != null &&
          p.parentPath.node.type === 'TryStatement' &&
          p.key === 'block'
        );
      }
      sCount += 1;
    }
    p = p.parentPath;
  }

  return false;
}