Sweet.js macros

macros.js

// for rebuilding an array without reassignment

macro rebuild {
    rule {$oldArr $newArr} => {
        $oldArr.length = 0
        $oldArr.push.apply($oldArr, $newArr)
    }
}

rebuild arr newArr;


// sugar for underscore's _.chain() method

let chain = macro {
    rule {$obj $($method) ... ~} => {
        _.chain($obj).$method ... .value()
    }
}

chain {a: 1, b: 2} groupBy(() => {}).pick(() => {})~;