AI代码解释 var__values=(this&&this.__values)||function(o){varm=typeofSymbol==="function"&&o[Symbol.iterator],i=0;if(m)returnm.call(o);return{next:function(){if(o&&i>=o.length)o=void0;return{value:o&&o[i++],done:!o};}};};vartext="Booh! 👻";try{for(vartext_1=__value...
functionLogOutput(tarage:Function,key:string,descriptor:any){letoriginalMethod=descriptor.value;letnewMethod=function(...args:any[]):any{letresult:any=originalMethod.apply(this,args);if(!this.loggedOutput){this.loggedOutput=newArray<any>();}this.loggedOutput.push({method:key,parameters:args,outpu...
if ("startDate" in emp) { console.log("Start Date: " + emp.startDate); } } 4.2 typeof 关键字 function padLeft(value: string, padding: string | number) { if (typeof padding === "number") { return Array(padding + 1).join(" ") + value; } if (typeof padding === "string"...
}[]): number; function pickCard(x: number): {suit: string; card: number; }; function pickCard(x): any { // Check to see if we're working with an object/array // if so, they gave us the deck and we'll pick the card if (typeof x == "object") { let pickedCard = Math...
hasInstance](val: unknown): val is PointLike { return !!val && typeof val === "object" && "x" in val && "y" in val && typeof val.x === "number" && typeof val.y === "number"; } } function f(value: unknown) { if (value instanceof Point) { // Can access both of ...
requiredPropA: 'This object is of type RuleA' }, { requiredPropB: 'This object is of type RuleB' } ] myRules.map((rule) => { if ((rule as RuleA).requiredPropA) { // do stuff } else { // do other stuff } }) 2018-03-19 21:02:40 ...
The above discussion makes sense as to why the length check is not enough for type narrowing, but what about when the index is known to contain a non null object because it has been retrieved from findIndex such as: const index = items.findIndex(item => somecondition); if (index !==...
class MyObject implements Comparable<MyObject> { age: number; compareTo(b: MyObject): number { if (this.age === b.age) { return 0; } return this.age > b.age ? 1 : -1; } } 这是个很有用的功能,可以确保我们在比较相同类型的对象。利用这个功能,我们还可以使用编辑器的代码补全。
We can set up cascade options in our relations, in the cases when we want our related object to be saved whenever the other object is saved. Let's change our photo's @OneToOne decorator a bit:export class Photo { // ... other columns @OneToOne(() => PhotoMetadata, (metadata) =...
// @ts-check let obj = {}; Object.defineProperty(obj, "x", { value: "hello", writable: false }); obj.x.toLowercase(); // ~~~ // error: // Property 'toLowercase' does not exist on type 'string'. // Did you mean 'toLowerCase'? obj.x = "...