chore: cleanup code to bring coverage back up

src/createColors.spec.ts

@@ -2,6 +2,83 @@ import test from 'ava'
 
 import { createColors } from './createColors'
 
+test('match colormap output', t => {
+  const actual = createColors([0, 0, 255], [0, 255, 128], 72)
+
+  t.deepEqual(actual, [[0, 0, 255, 1],
+  [0, 4, 253, 1],
+  [0, 7, 251, 1],
+  [0, 11, 250, 1],
+  [0, 14, 248, 1],
+  [0, 18, 246, 1],
+  [0, 22, 244, 1],
+  [0, 25, 242, 1],
+  [0, 29, 241, 1],
+  [0, 32, 239, 1],
+  [0, 36, 237, 1],
+  [0, 40, 235, 1],
+  [0, 43, 234, 1],
+  [0, 47, 232, 1],
+  [0, 50, 230, 1],
+  [0, 54, 228, 1],
+  [0, 57, 226, 1],
+  [0, 61, 225, 1],
+  [0, 65, 223, 1],
+  [0, 68, 221, 1],
+  [0, 72, 219, 1],
+  [0, 75, 217, 1],
+  [0, 79, 216, 1],
+  [0, 83, 214, 1],
+  [0, 86, 212, 1],
+  [0, 90, 210, 1],
+  [0, 93, 208, 1],
+  [0, 97, 207, 1],
+  [0, 101, 205, 1],
+  [0, 104, 203, 1],
+  [0, 108, 201, 1],
+  [0, 111, 200, 1],
+  [0, 115, 198, 1],
+  [0, 119, 196, 1],
+  [0, 122, 194, 1],
+  [0, 126, 192, 1],
+  [0, 129, 191, 1],
+  [0, 133, 189, 1],
+  [0, 136, 187, 1],
+  [0, 140, 185, 1],
+  [0, 144, 183, 1],
+  [0, 147, 182, 1],
+  [0, 151, 180, 1],
+  [0, 154, 178, 1],
+  [0, 158, 176, 1],
+  [0, 162, 175, 1],
+  [0, 165, 173, 1],
+  [0, 169, 171, 1],
+  [0, 172, 169, 1],
+  [0, 176, 167, 1],
+  [0, 180, 166, 1],
+  [0, 183, 164, 1],
+  [0, 187, 162, 1],
+  [0, 190, 160, 1],
+  [0, 194, 158, 1],
+  [0, 198, 157, 1],
+  [0, 201, 155, 1],
+  [0, 205, 153, 1],
+  [0, 208, 151, 1],
+  [0, 212, 149, 1],
+  [0, 215, 148, 1],
+  [0, 219, 146, 1],
+  [0, 223, 144, 1],
+  [0, 226, 142, 1],
+  [0, 230, 141, 1],
+  [0, 233, 139, 1],
+  [0, 237, 137, 1],
+  [0, 241, 135, 1],
+  [0, 244, 133, 1],
+  [0, 248, 132, 1],
+  [0, 251, 130, 1],
+  [0, 255, 128, 1]])
+})
+
 test('match actual colors', t => {
   let actual = createColors([150, 0, 90], [0, 0, 200], 72, [0, 1])
 

src/createColors.ts

@@ -8,20 +8,19 @@ export function createColors(from: RGB, to: RGB, shades: number, alpha: Alpha =
     to[1] - from[1],
     to[2] - from[2]
   ]
-  if (alpha) {
-    start.push(alpha[0])
-    diff.push(alpha[1] - alpha[0])
-  }
+
+  start.push(alpha[0])
+  diff.push(alpha[1] - alpha[0])
 
   const inc = 1 /
-  Math.max(shades - 1, 1)
+    Math.max(shades - 1, 1)
 
   for (let i = 0; i < shades; i++) {
     const color = [
       Math.round(start[0] + i * diff[0] * inc),
       Math.round(start[1] + i * diff[1] * inc),
       Math.round(start[2] + i * diff[2] * inc),
-      alpha ? start[3] + i * diff[3] * inc : 1
+      start[3] + i * diff[3] * inc
     ]
     rgba.push(color)
   }