Commit 29a7c83e authored by Ammar Alakkad's avatar Ammar Alakkad

Add color utils with relevant tests

parent 59a5a89c
/**
* Convert hex color to rgb array
*
* @param hex string
* @returns array|null
*/
export const hexToRgb = hex => {
// Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
const shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
const fullHex = hex.replace(shorthandRegex, (_m, r, g, b) => r + r + g + g + b + b);
const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(fullHex);
return result
? [parseInt(result[1], 16), parseInt(result[2], 16), parseInt(result[3], 16)]
: null;
};
export const textColorForBackground = backgroundColor => {
const [r, g, b] = hexToRgb(backgroundColor);
if (r + g + b > 500) {
return '#333333';
}
return '#FFFFFF';
};
import { textColorForBackground, hexToRgb } from '~/lib/utils/color_utils';
describe('Color utils', () => {
describe('Converting hex code to rgb', () => {
it('convert hex code to rgb', () => {
expect(hexToRgb('#000000')).toEqual([0, 0, 0]);
expect(hexToRgb('#ffffff')).toEqual([255, 255, 255]);
});
it('convert short hex code to rgb', () => {
expect(hexToRgb('#000')).toEqual([0, 0, 0]);
expect(hexToRgb('#fff')).toEqual([255, 255, 255]);
});
it('handle conversion regardless of the characters case', () => {
expect(hexToRgb('#f0F')).toEqual([255, 0, 255]);
});
});
describe('Getting text color for given background', () => {
// following tests are being ported from `text_color_for_bg` section in labels_helper_spec.rb
it('uses light text on dark backgrounds', () => {
expect(textColorForBackground('#222E2E')).toEqual('#FFFFFF');
});
it('uses dark text on light backgrounds', () => {
expect(textColorForBackground('#EEEEEE')).toEqual('#333333');
});
it('supports RGB triplets', () => {
expect(textColorForBackground('#FFF')).toEqual('#333333');
expect(textColorForBackground('#000')).toEqual('#FFFFFF');
});
});
});
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