Merge pull request #128 from launchcodedev/hidden

Adds $hidden directive

Author: joelgallant

app-config-default-extensions/index.js

@@ -18,6 +18,7 @@ module.exports = {
       tryDirective,
       ifDirective,
       eqDirective,
+      hiddenDirective,
       envDirective,
       envVarDirective,
       extendsDirective,
@@ -36,6 +37,7 @@ module.exports = {
       tryDirective(),
       ifDirective(),
       eqDirective(),
+      hiddenDirective(),
       v1Compat(),
       envDirective(aliases, environmentOverride, environmentSourceNames),
       envVarDirective(aliases, environmentOverride, environmentSourceNames),
@@ -59,6 +61,7 @@ module.exports = {
       tryDirective,
       ifDirective,
       eqDirective,
+      hiddenDirective,
       extendsDirective,
       extendsSelfDirective,
       overrideDirective,
@@ -69,6 +72,7 @@ module.exports = {
       tryDirective(),
       ifDirective(),
       eqDirective(),
+      hiddenDirective(),
       extendsDirective(),
       extendsSelfDirective(),
       overrideDirective(),

app-config-extensions/src/index.test.ts

@@ -6,6 +6,7 @@ import {
   tryDirective,
   ifDirective,
   eqDirective,
+  hiddenDirective,
   envDirective,
   envVarDirective,
   extendsDirective,
@@ -229,6 +230,69 @@ describe('$eq directive', () => {
   });
 });
 
+describe('$hidden directive', () => {
+  it('doesnt include hidden', async () => {
+    const source = new LiteralSource({
+      $hidden: {},
+    });
+
+    expect(await source.readToJSON([hiddenDirective()])).toEqual({});
+  });
+
+  it('merges hidden', async () => {
+    const source = new LiteralSource({
+      $hidden: {},
+      foo: true,
+    });
+
+    expect(await source.readToJSON([hiddenDirective()])).toEqual({ foo: true });
+  });
+
+  it('references hidden property', async () => {
+    const source = new LiteralSource({
+      $hidden: {
+        foo: 42,
+      },
+      baz: {
+        $hidden: 44,
+      },
+      foo: {
+        $extendsSelf: '$hidden.foo',
+      },
+      bar: {
+        $extendsSelf: 'baz.$hidden',
+      },
+    });
+
+    expect(await source.readToJSON([extendsSelfDirective(), hiddenDirective()])).toEqual({
+      baz: {},
+      foo: 42,
+      bar: 44,
+    });
+  });
+
+  it('references hidden property and processes it', async () => {
+    process.env.FOO = 'bar';
+
+    const source = new LiteralSource({
+      $hidden: {
+        foo: {
+          $envVar: 'FOO',
+        },
+      },
+      foo: {
+        $extendsSelf: '$hidden.foo',
+      },
+    });
+
+    expect(
+      await source.readToJSON([extendsSelfDirective(), hiddenDirective(), envVarDirective()]),
+    ).toEqual({
+      foo: 'bar',
+    });
+  });
+});
+
 describe('$extends directive', () => {
   it('fails if file is missing', async () => {
     const source = new LiteralSource({

app-config-extensions/src/index.ts

@@ -118,6 +118,13 @@ export function eqDirective(): ParsingExtension {
   );
 }
 
+/** Prpoerties that are removed, used by references */
+export function hiddenDirective(): ParsingExtension {
+  return forKey('$hidden', () => async (parse) => {
+    return parse({}, { shouldMerge: true });
+  });
+}
+
 /** Uses another file as overriding values, layering them on top of current file */
 export function overrideDirective(): ParsingExtension {
   return fileReferenceDirective('$override', { shouldOverride: true });

docs/guide/intro/extensions.md

@@ -181,6 +181,25 @@ $if:
   $else: bar
 ```
 
+## The `$hidden` Directive
+
+You can use `$hidden` anywhere - the values underneath it are not processed directly.
+This is useful for shared values.
+
+```yaml
+$hidden:
+  foo: 42
+
+bar:
+  baz:
+    $extendsSelf: '$hidden.foo'
+
+qux:
+  $extendsSelf: '$hidden.foo'
+```
+
+This results in `{ bar: { baz: 42 }, qux: 42 }`.
+
 ## The `$timestamp` Directive
 
 Allows injecting the current date and time into configuration. While this option is useful,