TypeScript Version: 1.8.34
Code
let canvas = document.createElement("canvas");
let context = canvas.getContext("2d");
let pattern: CanvasPattern = []; // !!!
context.fillStyle = pattern;
context.strokeStyle = 0; // !!!Expected behavior:
Fails to compile due to [] and 0 not being valid CanvasPatterns.
Actual behavior:
Successfully compiles, probably due to CanvasPattern being declared as an empty interface, which is obviously implemented by all objects. At runtime, the style is solid black.
// lib.d.ts
interface CanvasPattern {
}
//...
fillStyle: string | CanvasGradient | CanvasPattern;
//...
strokeStyle: string | CanvasGradient | CanvasPattern;
TypeScript Version: 1.8.34
Code
Expected behavior:
Fails to compile due to
[]and0not being validCanvasPatterns.Actual behavior:
Successfully compiles, probably due to
CanvasPatternbeing declared as an emptyinterface, which is obviously implemented by all objects. At runtime, the style is solid black.