[英]Angular Assigning ngIf class boolean properties when calling function to check for different data types
[英]Function argument types are not properly check when assigning functions
我在 TypeScript 遇到了一个奇怪的交互:
type Vector2 = { x: number; y: number };
type Vector3 = { x: number; y: number; z: number };
type Takes2 = (vec: Vector2) => void;
type Takes3 = (vec: Vector3) => void;
let f2: Takes2 = (vec) => console.log(vec.x + vec.y);
let f3: Takes3 = (vec) => console.log(vec.x + vec.y + vec.z);
// This makes sence - we call f2 with Vector3, so the "z" prop is going to be ignored
f3 = f2;
f3({ x: 1, y: 2, z: 5 }); // prints 3 (1 + 2)
// This makes no sence - we call f3 with Vector2, so we read undefined when we read vec.z
f2 = f3;
f2({ x: 1, y: 2 }); // prints NaN! (1 + 2 + undefined)
看起来当一个 function 被分配给另一个变量(或者我猜是作为参数传递)时,TypeScript 只检查类型是否“单向兼容”(arguments 中的一个可以分配给另一个),但不会麻烦检查参数类型兼容的方向是否与 function 分配的方向相匹配。
总是这样吗? 还是可以切换的编译器选项?
TypeScript 版本:4.4.4 tsconfig.json:
{
"compilerOptions": {
"target": "es5",
"downlevelIteration": true,
"lib": ["dom", "dom.iterable", "esnext"],
"allowJs": true,
"skipLibCheck": true,
"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
// "strict": true,
"forceConsistentCasingInFileNames": true,
"noImplicitAny": true,
"noImplicitReturns": true,
"noFallthroughCasesInSwitch": true,
"module": "esnext",
// "module": "commonjs",
"moduleResolution": "node",
"resolveJsonModule": true,
// "isolatedModules": true,
"noEmit": true,
"jsx": "react",
"baseUrl": ".",
"paths": {
"*": ["./src/*"]
}
},
"types": ["forge-viewer"],
"include": ["src"]
}
您正在寻找的标志是strictFunctionTypes 。
我在您的配置中注意到您已注释掉"strict": true
。 如果你离开严格模式(这是推荐的),那么strictFunctionTypes
就会被包含进来,你就会得到一个编译错误。
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