错误TS2339：类型“ {}”上不存在属性“ forEach”

Question

When I'm trying to compile this typescript with npm it told me this error: "error TS2339: Property 'forEach' does not exist on type '{}'."

the code is

export class TestComponent{
    array: yo[];
    check(){
        this.array.map(abc=>{
            abc.prop.forEach(ws=>{
                console.log(ws)
            })
        });
    }
}

but when I force the execute of the code it works perfectly :\\

Answer 1

The code works because TypeScript will emit the JavaScript even if there's an error during compilation. And because of the nature of JavaScript abc.prop probably is an array and has the forEach method.

And the error occurs because TypeScript can't know that abc.prop is an array. You have to either import the appropriate typings or create one for it.