Jamesernator

async def yieldfromexample():
    RESULT = yield from EXPR

# Would become
async def yieldfromexample():
    _i = aiter(EXPR)
    try:
        _y = await anext(_i)
    except StopAsyncIteration as _e:
        _r = _e.value

Jamesernator

async function drawCircles(mousedownEvent) {
    const { top, left } = theCanvas.getBoundingClientRect()
    for await (const clickEvent of clicks(theCanvas)) {
        const radius = Math.random() * 19 + 1 // Circles between 1-20 inclusive
        const color = randomColor()
        drawCircle(
            theCanvas,
            clickEvent.clientX - left,
            clickEvent.clientY - top,
            radius,

Jamesernator

Array<T>

Array<T>.prototype.*

• concat(: (T | Array<T>)[]): T[]
concat(items) 🔒
  • Returns a new array that is the concatenation of this and all items. Non-array parameters are treated as if they were arrays with single elements.
  • ES3
  • ['a'].concat('b', ['c', 'd']) → [ 'a', 'b', 'c', 'd' ]
• copyWithin(:number, :number, ?:number): this

Jamesernator

Boris the Spider
Swamp
Dry County
White Lightning
Murder By Numbers
Dreadmonboogaloo
Expresso Love
Lizard Life
Fuzzbox Voodoo
Makin' Thunderbirds

Jamesernator

export default async function doAbortable<R>(
    signal: AbortSignal | undefined,
    func: (abortSignal: AbortSignal) => R | Promise<R>,
): Promise<R> {
    const controller = new AbortController();
    const abortInner = () => controller.abort();
    if (signal?.aborted) {
        abortInner();
    } else {
        signal?.addEventListener("abort", abortInner, { once: true });

Jamesernator

Harden - Fixing the override mistake

The override mistake

The override mistake is a problem introduced with ES5's ability to mark properties as non-writable. When a property on the prototype of an object is marked non-writable, it makes the property unaddable on the object.

A notable example of this is if we freeze (which marks all properties as non-writable) on Object.prototype.