just/packages/array-range/index.js at diff · hmmhmmhm/just

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module.exports = range;

range(0, 5); // [0, 1, 2, 3, 4]

range(5); // [0, 1, 2, 3, 4]

range(-5); // [0, -1, -2, -3, -4]

range(0, 20, 5) // [0, 5, 10, 15]

range(0, -20, -5) // [0, -5, -10, -15]

function range(start, stop, step) {

if (start != null && typeof start != 'number') {

throw new Error('start must be a number or null');

}

if (stop != null && typeof stop != 'number') {

throw new Error('stop must be a number or null');

}

if (step != null && typeof step != 'number') {

throw new Error('step must be a number or null');

}

if (stop == null) {

stop = start || 0;

start = 0;

}

if (step == null) {

step = stop > start ? 1 : -1;

}

var toReturn = [];

var increasing = start < stop; //← here’s the change

for (; increasing ? start < stop : start > stop; start += step) {

toReturn.push(start);

}

return toReturn;

}