superfluous and costly sqrt

[redchair123]

https://github.com/dtao/nearest-color/blob/master/nearestColor.js#L70-L83 a square root is performed in every iteration. Since you are comparing square roots to other square roots, it would be faster to compare the square distances and take the square root at the end:

    for (var i = 0; i < colors.length; ++i) {
      rgb = colors[i].rgb;

      /* distance is the square of the actual distance */
      distance = (
        Math.pow(needle.r - rgb.r, 2) +
        Math.pow(needle.g - rgb.g, 2) +
        Math.pow(needle.b - rgb.b, 2)
      );

      /* comparison is still consistent: assuming a>0 and b>0, then a > b if and only if sqrt(a) > sqrt(b) */
      if (distance < minDistance) {
        minDistance = distance;
        value = colors[i];
      }
    }

    /* take the sqrt at the end */
    minDistance = Math.sqrt(minDistance);

[Dan Tao]

Good point! This should be easy enough to fix :)