i try to create a type which has a variable value as a property
For example:
const myProp: string = 'my prop';
type Foo ={
[myProp]: string
};
i expected that i can do:
const test: Foo = {
[myProp] = myProp
}
But get error of:
[ts] A computed property name in a type literal must directly refer to a built-in symbol.
If you want to declare a type that has the same property name as a string constant you could use the following syntax (lookup type syntax)
const myProp = 'my prop';
type Foo = {
[P in typeof myProp]: string
};
const test: Foo = {
[myProp]: myProp
}
If you want to have several of these keys you can use a union type :
const myProp = 'my prop';
const otherProp = "otherProp"
type Foo = {
[P in (typeof myProp | typeof otherProp)]: string
};
const test: Foo = {
[myProp]: myProp,
[otherProp]: otherProp
}
The typescript default libraries, actually provides a type that is equivalent to the above lookup type declaration, named Record. Using this you could write your type as:
type Foo2 = Record<typeof myProp, string>;
You will able to do this once next version of Typescript released.
This feature already available in typescript@next. If you want to, you can install it with:
npm install typescript@next --save-dev
Meanwhile you can use method provided by @Titian Cernicova-Dragomir
