Ref adjust. Closes #1807

hapijs · Jun 2, 2019 · 56f79b9 · 56f79b9
1 parent 295b97b
commit 56f79b9
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Showing 3 changed files with 75 additions and 2 deletions.
diff --git a/API.md b/API.md
@@ -422,6 +422,10 @@ References support the following arguments:
     - `contextPrefix` - overrides the default `$` context prefix signifier.
     - `ancestor` - if set to a number, sets the reference [relative starting point](#Relative-references). Cannot be combined
       with separator prefix characters. Defaults to the reference key prefix (or `1` if none present).
+    - `adjust` - a function with the signature `function(value)` where `value` is the resolved reference value and the return
+      value is the adjusted value to use. For example `(value) => value + 5` will add 5 to the resolved value. Note that the
+      `adjust` feature will not perform any type validation on the adjusted value and it must match the value expected by the
+      rule it is used in.
     - Other options can also be passed based on what [`Hoek.reach`](https://github.com/hapijs/hoek/blob/master/API.md#reachobj-chain-options) supports.
 
 Note that references can only be used where explicitly supported such as in `valid()` or `invalid()` rules. If upwards

diff --git a/lib/ref.js b/lib/ref.js
@@ -16,6 +16,7 @@ module.exports = exports = internals.Ref = class {
     constructor(key, options = {}) {
 
         Hoek.assert(typeof key === 'string', 'Invalid reference key:', key);
+        Hoek.assert(!options.adjust || typeof options.adjust === 'function', 'options.adjust must be a function');
 
         this.settings = Hoek.clone(options);
         this[internals.symbol] = true;
@@ -57,7 +58,12 @@ module.exports = exports = internals.Ref = class {
         Hoek.assert(!ancestor || ancestor <= state.ancestors.length, 'Invalid reference exceeds the schema root:', this.display);
 
         const target = this.isContext ? options.context : (ancestor ? state.ancestors[ancestor - 1] : value);
-        return Hoek.reach(target, this.key, this.settings);
+        let resolved = Hoek.reach(target, this.key, this.settings);
+        if (this.settings.adjust) {
+            resolved = this.settings.adjust(resolved);
+        }
+
+        return resolved;
     }
 
     toString() {
@@ -67,11 +73,17 @@ module.exports = exports = internals.Ref = class {
 
     describe() {
 
-        return {
+        const about = {
             type: this.isContext ? 'context' : 'ref',
             key: this.key,
             path: this.path
         };
+
+        if (this.settings.adjust) {
+            about.adjust = this.settings.adjust;
+        }
+
+        return about;
     }
 
     static isRef(ref) {

diff --git a/test/ref.js b/test/ref.js
@@ -400,6 +400,63 @@ describe('ref', () => {
         ]);
     });
 
+    it('sets adjust function', () => {
+
+        const adjust = (v) => 2 * v;
+        const ref = Joi.ref('b', { adjust });
+        const schema = Joi.object({
+            a: ref,
+            b: Joi.number()
+        });
+
+        Helper.validate(schema, [
+            [{ b: 5 }, true],
+            [{ a: 10, b: 5 }, true],
+            [{ a: 10, b: '5' }, true],
+            [{ a: 5 }, false, null, {
+                message: 'child "a" fails because ["a" must be one of [ref:b]]',
+                details: [{
+                    message: '"a" must be one of [ref:b]',
+                    path: ['a'],
+                    type: 'any.allowOnly',
+                    context: { value: 5, valids: [ref], label: 'a', key: 'a' }
+                }]
+            }],
+            [{ a: 5, b: 5 }, false, null, {
+                message: 'child "a" fails because ["a" must be one of [ref:b]]',
+                details: [{
+                    message: '"a" must be one of [ref:b]',
+                    path: ['a'],
+                    type: 'any.allowOnly',
+                    context: { value: 5, valids: [ref], label: 'a', key: 'a' }
+                }]
+            }]
+        ]);
+
+        expect(schema.describe()).to.equal({
+            type: 'object',
+            children: {
+                b: {
+                    type: 'number',
+                    flags: { unsafe: false },
+                    invalids: [Infinity, -Infinity]
+                },
+                a: {
+                    type: 'any',
+                    flags: { allowOnly: true },
+                    valids: [
+                        {
+                            type: 'ref',
+                            key: 'b',
+                            path: ['b'],
+                            adjust
+                        }
+                    ]
+                }
+            }
+        });
+    });
+
     it('uses ref as a valid value (empty key)', async () => {
 
         const ref = Joi.ref('');