fix(suggestion): prefixColors API type to embrace string type (#439)

README.md

@@ -335,7 +335,7 @@ For more details, visit https://github.com/open-cli-tools/concurrently
   - `prefix`: the prefix type to use when logging processes output.
     Possible values: `index`, `pid`, `time`, `command`, `name`, `none`, or a template (eg `[{time} process: {pid}]`).
     Default: the name of the process, or its index if no name is set.
-  - `prefixColors`: a list of colors as supported by [chalk](https://www.npmjs.com/package/chalk) or `auto` for an automatically picked color.
+  - `prefixColors`: a list of colors or a string as supported by [chalk](https://www.npmjs.com/package/chalk) and additional style `auto` for an automatically picked color.
     If concurrently would run more commands than there are colors, the last color is repeated, unless if the last color value is `auto` which means following colors are automatically picked to vary.
     Prefix colors specified per-command take precedence over this list.
   - `prefixLength`: how many characters to show when prefixing with `command`. Default: `10`

src/concurrently.ts

@@ -62,9 +62,22 @@ export type ConcurrentlyOptions = {
     group?: boolean;
 
     /**
-     * Comma-separated list of chalk colors to use on prefixes.
+     * A comma-separated list of chalk colors or a string for available styles listed below to use on prefixes.
+     * If there are more commands than colors, the last color will be repeated.
+     *
+     * Available modifiers:
+     * - `reset`, `bold`, `dim`, `italic`, `underline`, `inverse`, `hidden`, `strikethrough`
+     *
+     * Available colors:
+     * - `black`, `red`, `green`, `yellow`, `blue`, `magenta`, `cyan`, `white`, `gray`,
+     * any hex values for colors (e.g. `#23de43`) or `auto` for an automatically picked color
+     *
+     * Available background colors:
+     * - `bgBlack`, `bgRed`, `bgGreen`, `bgYellow`, `bgBlue`, `bgMagenta`, `bgCyan`, `bgWhite`
+     *
+     * @see {@link https://www.npmjs.com/package/chalk} for more information.
      */
-    prefixColors?: string[];
+    prefixColors?: string | string[];
 
     /**
      * Maximum number of commands to run at once.

src/prefix-color-selector.ts

@@ -58,8 +58,9 @@ function* createColorGenerator(customColors: string[]): Generator<string, string
 export class PrefixColorSelector {
     private colorGenerator: Generator<string, string>;
 
-    constructor(customColors: string[] = []) {
-        this.colorGenerator = createColorGenerator(customColors);
+    constructor(customColors: string | string[] = []) {
+        const normalizedColors = typeof customColors === 'string' ? [customColors] : customColors;
+        this.colorGenerator = createColorGenerator(normalizedColors);
     }
 
     /** A list of colors that are readable in a terminal. */