feat(args): add defaultHint opt, update usage()

- add UsageOpts.showDefaults to display arg default vals - add ArgSpecBase.defaultHint for default vals for display purposes
thi-ng · Jan 11, 2021 · f8a4146 · f8a4146
1 parent 841b062
commit f8a4146
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Showing 2 changed files with 28 additions and 1 deletion.
diff --git a/packages/args/src/api.ts b/packages/args/src/api.ts
@@ -4,6 +4,7 @@ export interface ArgSpecBase {
     alias?: string;
     desc?: string;
     hint?: string;
+    defaultHint?: string;
     fn?: Fn<string, boolean>;
 }
 
@@ -92,16 +93,29 @@ export interface UsageOpts {
      * @defaultValue true
      */
     color: Partial<ColorTheme> | false;
+    /**
+     * If true (default), display argument default values.
+     *
+     * @defaultValue true
+     */
+    showDefaults: boolean;
 }
 
+/**
+ * Color theme for {@link usage}. Each item is an ANSI color code:
+ *
+ * https://en.wikipedia.org/wiki/ANSI_escape_code#3-bit_and_4-bit
+ */
 export interface ColorTheme {
+    default: number;
     hint: number;
     multi: number;
     param: number;
     required: number;
 }
 
 export const DEFAULT_THEME: ColorTheme = {
+    default: 95,
     hint: 90,
     multi: 90,
     param: 96,

diff --git a/packages/args/src/usage.ts b/packages/args/src/usage.ts
@@ -3,6 +3,7 @@ import {
     kebab,
     padRight,
     repeat,
+    stringify,
     stripAnsi,
     wordWrapLines,
 } from "@thi.ng/strings";
@@ -15,6 +16,7 @@ export const usage = <T extends IObjectOf<any>>(
     opts = {
         lineWidth: 80,
         paramWidth: 32,
+        showDefaults: true,
         ...opts,
     };
     const theme =
@@ -45,10 +47,21 @@ export const usage = <T extends IObjectOf<any>>(
                       isRequired ? theme.required! : theme.multi!
                   )
                 : "";
+            const defaults =
+                opts.showDefaults && spec.default
+                    ? ansi(
+                          ` (default: ${stringify()(
+                              spec.defaultHint != undefined
+                                  ? spec.defaultHint
+                                  : spec.default
+                          )})`,
+                          theme.default
+                      )
+                    : "";
             return (
                 padRight(opts.paramWidth!)(params, stripAnsi(params).length) +
                 wordWrapLines(
-                    prefix + (spec.desc || ""),
+                    prefix + (spec.desc || "") + defaults,
                     opts.lineWidth! - opts.paramWidth!
                 )
                     .map((l, i) => (i > 0 ? indent : "") + l)