How can object property be referenced using bracket notation in TypeScript?
In traditional JavaScript, it can be done like this:
getValue(object, key) {
return object[key];
}
By calling
getValue({someKey: 1}, "someKey")1.
However, when attempting to do this in TypeScript, an error is encountered:
TS1003: Identifier expected. Name expected.What is the correct way to achieve this in TypeScript?
If you are looking for a way to ensure type safety in your code, you may want to consider utilizing the keyof keyword:
interface YourObj {
someKey: string;
someOtherKey: number;
}
function getValue(obj: YourObj, key: keyof YourObj) {
return obj[key];
}
console.log("Value of object = " + getValue({someKey: "someValue", someOtherKey: 1}, "someKey"))
By using keyof, you will receive compilation errors if you try to call getValue on anything other than an object that matches the structure of YourObj or with a key that is not defined in YourObj
In Typescript, JavaScript is considered a strict superset, making JavaScript code compatible with Typescript.
When accessing object properties in Typescript, both the dot notation and bracket notation are valid options. Executing the code example below will not produce any errors or warnings.
If you need further assistance, it's recommended to provide a minimal, reproducible example.
Check out this TypeScript Playground Demo
function returnValue(obj: any, key: string) {
return obj[key];
}
console.log("Object value = " + returnValue({someKey: 1}, "someKey"))
Object value = 1
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