Basic syntax
const [x=3, y] = []
console.log(x, y) // 3 undefinedComputed on demand
Default values are computed when they are needed:
function tralala() {
return "tralala string"
}
const {computed=tralala()} = {}
console.log(computed) // tralala stringRefer to other variables
Default value an refer to other variables in the same pattern:
const [x=3, y=x] = []; // x=3; y=3
const [i=3, j=x] = [7]; // i=7; j=7
const [k=3, l=x] = [7, 2]; // k=7; l=2