30秒学会 JavaScript 片段 – geometricProgression

Initializes an array containing the numbers in the specified range where start and end are inclusive and the ratio between two terms is step.
Returns an error if step equals 1.

Use Array.from(), Math.log() and Math.floor() to create an array of the desired length, Array.prototype.map() to fill with the desired values in a range.
Omit the second argument, start, to use a default value of 1.
Omit the third argument, step, to use a default value of 2.

代码片段

const geometricProgression = (end, start = 1, step = 2) =>
  Array.from({ length: Math.floor(Math.log(end / start) / Math.log(step)) + 1 }).map(
    (v, i) => start * step ** i
  );

使用样例

geometricProgression(256); // [1, 2, 4, 8, 16, 32, 64, 128, 256]
geometricProgression(256, 3); // [3, 6, 12, 24, 48, 96, 192]
geometricProgression(256, 1, 4); // [1, 4, 16, 64, 256]