Merge branch 'master' of https://github.com/okbel/e-comm-example

lib/colors.ts

@@ -14,3 +14,37 @@ export function getRandomPairOfColors() {
   // Returns a pair of colors
   return [colors[idx], colors[idx2]]
 }
+
+function hexToRgb(hex: string = '') {
+  // @ts-ignore
+  const match = hex.toString(16).match(/[a-f0-9]{6}|[a-f0-9]{3}/i)
+
+  if (!match) {
+    return [0, 0, 0]
+  }
+
+  let colorString = match[0]
+
+  if (match[0].length === 3) {
+    colorString = colorString
+      .split('')
+      .map((char: string) => {
+        return char + char
+      })
+      .join('')
+  }
+
+  const integer = parseInt(colorString, 16)
+  const r = (integer >> 16) & 0xff
+  const g = (integer >> 8) & 0xff
+  const b = integer & 0xff
+
+  return [r, g, b]
+}
+
+export function isDark(color = '') {
+  // Equation from http://24ways.org/2010/calculating-color-contrast
+  const rgb = hexToRgb(color)
+  const res = (rgb[0] * 299 + rgb[1] * 587 + rgb[2] * 114) / 1000
+  return res < 128
+}