added self referencing and function execution

added changelog file

CHANGELOG.md

@@ -0,0 +1,4 @@
+# Change Log
+
+This project adheres to [Semantic Versioning](http://semver.org/).  
+Every release, along with the migration instructions, is documented on the Github [Releases](https://github.com/docker/pulpo/releases) page.

README.md

@@ -99,6 +99,44 @@ Hydrate also allows for a second argument to be passed in that contains options:
 * cast (**default true**) - whether or not to cast the value before validating
 * validate (**default true**) - whether or not to validate a given value
 
+#### Referencing Other Configuration Values
+It is possible to reference other values in the configuration, which will be populated with resolved values found in the referenced key. This works for both **default** values and passed in values:
+
+```js
+const schema = new Pulpo({...schema...});
+
+const config = schema.hydrate({
+  server: {
+    port: 8888,
+    hostname: 'localhost',
+    host: 'http://${server.hostname}:${server.port}'
+  }
+});
+
+console.log(config.server.host);
+// http://localhost:8888
+```
+
+#### Using Functions for Configuration Values
+When needed, a function can be passed in as a **config** or **default** value. These functions are passed two arguments: the config object and the string path of the property being resolved:
+
+```js
+const schema = new Pulpo({...schema...});
+
+const config = schema.hydrate({
+  server: {
+    port: 8888,
+    hostname: 'localhost',
+    host: (config) => `http://${config['server.hostname']}:${config['server.port']}`
+  }
+});
+
+console.log(config.server.host);
+// http://localhost:8888
+```
+
+**Note**: Configuration values are accessed through their full dot-notation strings
+
 Properties
 ---
 Properties are definitions for a given configuration key.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@bonito/pulpo",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "Configuration mechanism",
   "author": "Patrick Camacho <[email protected]>",
   "license": "MIT",
@@ -17,7 +17,8 @@
     "build": "tsc",
     "deps": "next-update --tldr --keep",
     "start": "npm run -s test -- --watch --coverage",
-    "test": "jest"
+    "test": "jest",
+    "prepublish": "npm run -s test && npm run -s build"
   },
   "devDependencies": {
     "jest-cli": "15.1.1",

src/schema.ts

@@ -24,6 +24,34 @@ export interface ParsedSchemaDefinition {
   [optName: string]: Property;
 }
 
+interface HydratedConfig {
+  [optName: string]: any;
+}
+
+function stringLookup(str: string, config: HydratedConfig): string {
+  return str.replace(/(\$\{(.*)\})/gi, (match, group1, key) => {
+    return dotty.get(config, key);
+  });
+}
+
+function getter(config: HydratedConfig, value: any, path: string, validate: boolean): any {
+  let resolvedValue: any;
+
+  switch (typeof value) {
+    case 'function':
+      resolvedValue = value(config, path);
+      break;
+    case 'string':
+      resolvedValue = stringLookup(value, config);
+      break;
+    default:
+      resolvedValue = value;
+  }
+
+  if (validate) this.definition[path].validate(resolvedValue);
+  return resolvedValue;
+};
+
 export default class Schema {
   definition: ParsedSchemaDefinition;
 
@@ -60,28 +88,32 @@ export default class Schema {
   }
 
   hydrate(rawConfig: Object, options: HydrateOptionsDefinition = {}): Object {
-    const hydratedConfig = Object.keys(this.definition).reduce((obj, key) => {
+    const flags = {
+      transform: !Reflect.has(options, 'transform') || options.transform,
+      cast: !Reflect.has(options, 'cast') || options.cast,
+      validate: !Reflect.has(options, 'validate') || options.validate,
+    }
+
+    // Loop over and hydrate the object with getters
+
+    const hydratedConfig: HydratedConfig = Object.keys(this.definition).reduce((obj, key) => {
       const property = this.definition[key];
 
       let value = property.resolve(rawConfig);
 
-      if (!Reflect.has(options, 'transform') || options.transform) {
-        value = property.transform(value, rawConfig);
-      }
+      if (flags.transform) value = property.transform(value, rawConfig);
+      if (flags.cast) value = property.cast(value);
 
-      if (!Reflect.has(options, 'cast') || options.cast) {
-        value = property.cast(value);
-      }
+      Object.defineProperty(obj, key, {get:  getter.bind(this, obj, value, key, flags.validate) });
+      return obj
+    }, {});
 
-      if (!Reflect.has(options, 'validate') || options.validate) {
-        property.validate(value);
-      }
+    return Object.keys(this.definition).reduce((obj: HydratedConfig, key: string) => {
+      const value: any = hydratedConfig[key];
 
-      dotty.put(obj, key, value);
+      if (value) dotty.put(obj, key, value);
       return obj;
     }, {});
-
-    return hydratedConfig;
   }
 }
 

test/fixtures/self-referencing-schema.json

@@ -0,0 +1,13 @@
+{
+  "foo": {
+    "bar": {
+      "description": "nested schema key",
+      "type": "string",
+      "default": "${baz}/foo"
+    }
+  },
+  "baz": {
+    "description": "top level value",
+    "type": "string"
+  }
+}

test/integration/schema.spec.ts

@@ -2,6 +2,7 @@
 import Schema from '../../src/schema';
 import nestedSchema = require('../fixtures/nested-schema.json');
 import brokenNestedSchema = require('../fixtures/broken-nested-schema.json');
+import selfReferencingSchema = require('../fixtures/self-referencing-schema.json');
 
 describe('Resolve', () => {
   it('Accepts a provided value', () => {
@@ -92,7 +93,7 @@ describe('Cast and Validate', () => {
       number: {
         description: 'description',
         type: 'number',
-        default: 8888,
+        default: () => 8888,
       },
       string: {
         description: 'description',
@@ -102,7 +103,7 @@ describe('Cast and Validate', () => {
       boolean: {
         description: 'description',
         type: 'boolean',
-        default: false,
+        default: () => false,
       },
       array: {
         description: 'description',
@@ -112,7 +113,7 @@ describe('Cast and Validate', () => {
       object: {
         description: 'description',
         type: 'object',
-        default: {},
+        default: () => {},
       }
     });
 
@@ -172,3 +173,15 @@ describe('parsing nested schemas', () => {
     });
   });
 });
+
+describe('parsing self referencing strings', () => {
+  it('handles self references', () => {
+    const schema = new Schema(selfReferencingSchema);
+    expect(schema.hydrate({ baz: 'testing' })).toEqual({
+      foo: {
+        bar: 'testing/foo'
+      },
+      baz: 'testing'
+    });
+  });
+});