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type U = TypeA | TypeB;
interface TypeA {
kind: 'A';
a: number;
}
interface TypeB {
kind: 'B';
b: string;
}
function assertNever(x: never) {
return x;
}
function IfWithString(val: U) {
if (val['kind'] === 'B') {
return val.b;
} else {
return val.a;
}
}
function SwitchWithString(val: U) {
switch (val['kind']) {
case 'A':
return val.a;
case 'B':
return val.b;
default:
return assertNever(val);
}
}
function IfWithTemplate(val: U) {
if (val[`kind`] === 'B') {
return val.b;
} else {
return val.a;
}
}
function SwitchWithTemplate(val: U) {
switch (val[`kind`]) {
case 'A':
return val.a;
case 'B':
return val.b;
default:
return assertNever(val);
}
}
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