Here is the setter I created in TypeScript:
public set data(data: Array<Data>) {
console.log(data[0].getterProperty);
console.log(data[0] instanceof Data);
console.log(typeof data[0]);
this.setGridDataIfReady();
}
If data contains only one item, the output is:
undefined
false
object
I am confused as to why this is happening. Shouldn't the array only contain objects of type Data since that's what I specified?
It's important to remember that Typescript is a statically typed language that compiles down to JavaScript during runtime. This means that even though you define types in Typescript, the actual code being executed is JavaScript which can lead to unexpected behaviors.
While you may specify the type of an array as "Data" in your Typescript code, once transpiled, the runtime type becomes "Object". Unlike Java, where passing in an incorrect type would result in an Exception, Typescript does not provide this level of type safety during runtime.
If you truly want to ensure type safety and catch any errors at runtime, make sure that all entries in your array are created using the "new Data" constructor. By setting the constructor of the object, you can use the "instanceof Data" check to verify the type of each entry.
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