safe-resolve-non-thenable.js

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// |jit-test| skip-if: getBuildConfiguration("release_or_beta")

//

// JS::SafeResolve fast path: non-objects and inert objects should fulfill

// synchronously, exactly like JS::ResolvePromise.

function observe(p) {

  let fulfilled = null, rejected = null;

  p.then(v => { fulfilled = {value: v}; },

         e => { rejected  = {reason: e}; });

  drainJobQueue();

  return {fulfilled, rejected};

// Primitives.

for (const value of [undefined, null, 0, 42, "hello", true, Symbol("s"), 1n]) {

  const {promise} = Promise.withResolvers();

  safeResolvePromise(promise, value);

  const o = observe(promise);

  assertEq(o.rejected, null);

  assertEq(o.fulfilled !== null, true);

  assertEq(o.fulfilled.value, value);

// Plain object without "then" anywhere on the chain.

  const {promise} = Promise.withResolvers();

  const obj = Object.create(null);

  safeResolvePromise(promise, obj);

  const o = observe(promise);

  assertEq(o.rejected, null);

  assertEq(o.fulfilled.value, obj);

// Plain object with a non-callable "then" data property: spec fulfills with

// the object as-is.

  const {promise} = Promise.withResolvers();

  const obj = {then: 42};

  safeResolvePromise(promise, obj);

  const o = observe(promise);

  assertEq(o.rejected, null);

  assertEq(o.fulfilled.value, obj);

// Array (no own "then"; Array.prototype has no "then" either).

  const {promise} = Promise.withResolvers();

  const arr = [1, 2, 3];

  safeResolvePromise(promise, arr);

  const o = observe(promise);

  assertEq(o.rejected, null);

  assertEq(o.fulfilled.value, arr);