The fetch goes on in the background, and it’ll call you back when the response arrives. So for example, when you call fetch(), instead of blocking, it returns a Promise object immediately. They represent values that will become available later. What to say? Promises are the building blocks of asynchronous JS programming. Never mind how hard it is it barely even makes sense as a thing to do. Writing just one paragraph about promises is like eating just one potato chip. and then write them back to the canvas:ĭuring standardization, typed arrays picked up methods like. Var pixels = image.data // a Uint8ClampedArray object Var image = context.getImageData(0, 0, canvas.width, canvas.height) They’re handy whenever you need to process large volumes of raw binary or numeric data.įor example, if the Canvas rendering context is missing a feature you want, and if you’re feeling sufficiently hardcore about it, you can just implement it yourself: These were all standardized as part of WebGL, but they’ve been used in many other APIs since then, including Canvas, the Web Audio API, and WebRTC. One more quick warning: Many of the features below are not widely implemented yet.ĮS6 standardizes some features that were previously in other standards, or widely implemented but nonstandard. If you haven’t read the other parts of the series, take a look this installment may not be the best place to start! “On your left, you can see typed arrays…” Consider it a fun tour of all the closets and oddly-shaped upstairs rooms in this mansion of a language. This post covers over a dozen more new features that we never got around to talking about at length. Last week’s article on ES6 modules wrapped up a 4-month survey of the major new features in ES6. ES6 In Depth is a series on new features being added to the JavaScript programming language in the 6th Edition of the ECMAScript standard, ES6 for short.
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