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sinelaw/optional-args.js

Last active September 9, 2015 20:50
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optional args using polymorphic records + record field constraints
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optional-args.js
// foo :: { 0: Num, 1: Maybe Num } -> Num
function foo(a, opt_b) {
var b = opt_b == undefined ? 3 : opt_b;
return a + b;
}
// foo here inferred to have this type:
// RowFields r Maybe => { 0: Num | r } -> b
foo(3); // translated to: foo { 0 = 3 | .. }
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