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//// [optionalPropertiesSyntax.ts]
interface fnSigs {
//functions signatures can be optional
fn(): void;
fn?(): void; //err
fn2?(): void;
}
interface callSig {
//Call signatures can't be optional
(): any;
()?: any; //err
?(): any; //err
}
interface constructSig {
//Construct signatures can't be optional
new (): any;
new ()?: any; //err
new ?(): any; //err
}
interface propertySig {
//Property signatures can be optional
prop: any;
prop?: any;
prop2?: any;
}
interface indexSig {
//Index signatures can't be optional
[idx: number]: any;
[idx: number]?: any; //err
? [idx: number]: any; //err
[idx?: number]: any; //err
}
//// [optionalPropertiesSyntax.js]
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