ecmascript-5

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 I'm currently developing a 2D graphic library in JavaScript, and now I'm sticking with the background texture transforming problems. I want to set the background texture (property fillStyle ) of a canvas context ( CanvasRenderingContext2D ) to an image ( CanvasPattern ). It's easy to assign an image to the fillStyle . But the only problem is that, the image can't actually be translated, scaled nor skewed. I've looked up MDN, it says there's a prototype called setTransform() . With this API

问题 In ES5, Boolean.prototype is a Boolean object: The Boolean prototype object is itself a Boolean object (its [[Class]] is "Boolean") whose value is false. In ES6 / ES2015, it isn't: The Boolean prototype object is an ordinary object. It is not a Boolean instance and does not have a [[BooleanData]] internal slot. In ES2016, it is once again: The Boolean prototype is itself a Boolean object; it has a [[BooleanData]] internal slot with the value false. (and it remains so in ES2017 as well.) The

问题 I have a typescript 2 class that targets ES5. I'm getting the err in the subject line in the console when I run it. The switch statement works fine, but increment() and decrement() methods don't execute. class MyClass extends React.Component{ ... increment() { console.log('increment()') ... } decrement() { console.log('decrement()') ... } buttonClick(btn) { console.log(btn) switch (btn) { case "prev": console.log('switch prev') this.decrement(); //this.decrement; break; default: console.log(

问题 I have a typescript 2 class that targets ES5. I'm getting the err in the subject line in the console when I run it. The switch statement works fine, but increment() and decrement() methods don't execute. class MyClass extends React.Component{ ... increment() { console.log('increment()') ... } decrement() { console.log('decrement()') ... } buttonClick(btn) { console.log(btn) switch (btn) { case "prev": console.log('switch prev') this.decrement(); //this.decrement; break; default: console.log(

问题 I am trying to use Dygraph library in an Angular 6 project. It works perfectly in Chrome / FF, however it does not work in IE11. I installed the library through npm, and installed the @types from https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/dygraphs I imported the library in my module using: import { default as Dygraph } from 'dygraphs'; When I open the page on IE11, loading stops on: this.xticks.push({pos, label, has_tick}); With error SCRIPT1003: Expected ':'. . The

问题 Consider this code: (function a() { // Nested function function b() { console.log("Works!"); } b(); })(); This code works, but would it be possible (in theory) to call b() if the name is inside a string (i.e. dynamic)? If b() would be declared in the global scope, we could use window[stringContainingName](); . Is there a possibility in this case? This is only a theoretical question! I know that such code is bad design. 回答1: This code works, but would it be possible (in theory) to call b() if

问题 I am using the TypeScript flavor of create-react-app: npx create-react-app my-app --typescript When I build the app, the bundle still includes post-ES5 code such as Symbol. What am I missing? My tsconfig file: { "compilerOptions": { "target": "es5", "lib": [ "dom", "dom.iterable", "esnext" ], "allowJs": true, "skipLibCheck": true, "esModuleInterop": true, "allowSyntheticDefaultImports": true, "strict": true, "forceConsistentCasingInFileNames": true, "module": "esnext", "moduleResolution":