Update SDK to use type-specific getters

src/remote-config/remote-config-api.ts

@@ -361,7 +361,7 @@ export interface ServerTemplateOptions {
    * intended before it connects to the Remote Config backend, and so that
    * default values are available if none are set on the backend.
    */
-  defaultConfig?: ServerConfig,
+  defaultConfig?: { [key: string]: string | number | boolean };
 
   /**
    * Enables integrations to use template data loaded independently. For
@@ -385,7 +385,7 @@ export interface ServerTemplate {
   /**
    * A {@link ServerConfig} that contains default Config values.
    */
-  defaultConfig: ServerConfig;
+  defaultConfig: { [key: string]: string | number | boolean };
 
   /**
    * Evaluates the current template to produce a {@link ServerConfig}.
@@ -537,4 +537,89 @@ export interface ListVersionsOptions {
 /**
  * Represents the configuration produced by evaluating a server template.
  */
-export type ServerConfig = { [key: string]: string | boolean | number }
+export interface ServerConfig {
+
+  /**
+   * Gets the value for the given key as a boolean.
+   *
+   * Convenience method for calling <code>serverConfig.getValue(key).asBoolean()</code>.
+   *
+   * @param key - The name of the parameter.
+   *
+   * @returns The value for the given key as a boolean.
+   */
+  getBoolean(key: string): boolean;
+
+  /**
+   * Gets the value for the given key as a number.
+   *
+   * Convenience method for calling <code>serverConfig.getValue(key).asNumber()</code>.
+   *
+   * @param key - The name of the parameter.
+   *
+   * @returns The value for the given key as a number.
+   */
+  getNumber(key: string): number;
+
+  /**
+   * Gets the value for the given key as a string.
+   * Convenience method for calling <code>serverConfig.getValue(key).asString()</code>.
+   *
+   * @param key - The name of the parameter.
+   *
+   * @returns The value for the given key as a string.
+   */
+  getString(key: string): string;
+
+  /**
+   * Gets the {@link Value} for the given key.
+   *
+   * @param key - The name of the parameter.
+   *
+   * @returns The value for the given key.
+   */
+  getValue(key: string): Value;
+}
+
+/**
+ * Wraps a parameter value with metadata and type-safe getters.
+ * 
+ * Type-safe getters insulate application logic from remote
+ * changes to parameter names and types.
+ */
+export interface Value {
+
+  /**
+   * Gets the value as a boolean.
+   *
+   * The following values (case insensitive) are interpreted as true:
+   * "1", "true", "t", "yes", "y", "on". Other values are interpreted as false.
+   */
+  asBoolean(): boolean;
+
+  /**
+   * Gets the value as a number. Comparable to calling <code>Number(value) || 0</code>.
+   */
+  asNumber(): number;
+
+  /**
+   * Gets the value as a string.
+   */
+  asString(): string;
+
+  /**
+   * Gets the {@link ValueSource} for the given key.
+   */
+  getSource(): ValueSource;
+}
+
+/**
+ * Indicates the source of a value.
+ *
+ * <ul>
+ *   <li>"static" indicates the value was defined by a static constant.</li>
+ *   <li>"default" indicates the value was defined by default config.</li>
+ *   <li>"remote" indicates the value was defined by fetched config.</li>
+ * </ul>
+ */
+export type ValueSource = 'static' | 'default' | 'remote';

src/remote-config/remote-config.ts

@@ -30,13 +30,14 @@ import {
   Version,
   ExplicitParameterValue,
   InAppDefaultValue,
-  ParameterValueType,
   ServerConfig,
   RemoteConfigParameterValue,
   EvaluationContext,
   ServerTemplateData,
   ServerTemplateOptions,
   NamedCondition,
+  Value,
+  ValueSource,
 } from './remote-config-api';
 
 /**
@@ -296,7 +297,7 @@ class ServerTemplateImpl implements ServerTemplate {
   constructor(
     private readonly apiClient: RemoteConfigApiClient,
     private readonly conditionEvaluator: ConditionEvaluator,
-    public readonly defaultConfig: ServerConfig = {}
+    public readonly defaultConfig: { [key: string]: string | number | boolean } = {}
   ) { }
 
   /**
@@ -326,10 +327,10 @@ class ServerTemplateImpl implements ServerTemplate {
     const evaluatedConditions = this.conditionEvaluator.evaluateConditions(
       this.cache.conditions, context);
 
-    const evaluatedConfig: ServerConfig = {};
+    const evaluatedConfig: { [key: string]: string } = {};
 
     for (const [key, parameter] of Object.entries(this.cache.parameters)) {
-      const { conditionalValues, defaultValue, valueType } = parameter;
+      const { conditionalValues, defaultValue } = parameter;
 
       // Supports parameters with no conditional values.
       const normalizedConditionalValues = conditionalValues || {};
@@ -352,7 +353,7 @@ class ServerTemplateImpl implements ServerTemplate {
 
       if (parameterValueWrapper) {
         const parameterValue = (parameterValueWrapper as ExplicitParameterValue).value;
-        evaluatedConfig[key] = this.parseRemoteConfigParameterValue(valueType, parameterValue);
+        evaluatedConfig[key] = parameterValue;
         continue;
       }
 
@@ -367,47 +368,62 @@ class ServerTemplateImpl implements ServerTemplate {
       }
 
       const parameterDefaultValue = (defaultValue as ExplicitParameterValue).value;
-      evaluatedConfig[key] = this.parseRemoteConfigParameterValue(valueType, parameterDefaultValue);
+      evaluatedConfig[key] = parameterDefaultValue;
     }
 
-    const mergedConfig = {};
-
-    // Merges default config and rendered config, prioritizing the latter.
-    Object.assign(mergedConfig, this.defaultConfig, evaluatedConfig);
-
-    // Enables config to be a convenient object, but with the ability to perform additional
-    // functionality when a value is retrieved.
-    const proxyHandler = {
-      get(target: ServerConfig, prop: string) {
-        return target[prop];
-      }
-    };
-
-    return new Proxy(mergedConfig, proxyHandler);
+    return new ServerConfigImpl(evaluatedConfig, this.defaultConfig);
   }
+}
 
-  /**
-   * Private helper method that coerces a parameter value string to the {@link ParameterValueType}.
-   */
-  private parseRemoteConfigParameterValue(parameterType: ParameterValueType | undefined,
-    parameterValue: string): string | number | boolean {
-    const BOOLEAN_TRUTHY_VALUES = ['1', 'true', 't', 'yes', 'y', 'on'];
-    const DEFAULT_VALUE_FOR_NUMBER = 0;
-    const DEFAULT_VALUE_FOR_STRING = '';
-
-    if (parameterType === 'BOOLEAN') {
-      return BOOLEAN_TRUTHY_VALUES.indexOf(parameterValue) >= 0;
-    } else if (parameterType === 'NUMBER') {
-      const num = Number(parameterValue);
-      if (isNaN(num)) {
-        return DEFAULT_VALUE_FOR_NUMBER;
-      }
-      return num;
+class ServerConfigImpl implements ServerConfig {
+  constructor(
+    private readonly evaluatedConfig: { [key: string]: string },
+    private readonly defaultConfig: { [key: string]: string | number | boolean }
+  ){}
+  getBoolean(key: string): boolean {
+    return this.getValue(key).asBoolean();
+  }
+  getNumber(key: string): number {
+    return this.getValue(key).asNumber();
+  }
+  getString(key: string): string {
+    return this.getValue(key).asString();
+  }
+  getValue(key: string): Value {
+    if (key in this.evaluatedConfig) {
+      return new ValueImpl('remote', this.evaluatedConfig[key]);
+    } else if (key in this.defaultConfig) {
+      return new ValueImpl('default', String(this.defaultConfig[key]));
     } else {
-      // Treat everything else as string
-      return parameterValue || DEFAULT_VALUE_FOR_STRING;
+      return new ValueImpl('static');
+    }
+  }
+}
+
+class ValueImpl implements Value {
+  static BOOLEAN_TRUTHY_VALUES = ['1', 'true', 't', 'yes', 'y', 'on'];
+  static DEFAULT_VALUE_FOR_NUMBER = 0;
+  static DEFAULT_VALUE_FOR_STRING = '';
+  constructor(
+    private readonly source: ValueSource,
+    private readonly value = ValueImpl.DEFAULT_VALUE_FOR_STRING){}
+  asBoolean(): boolean {
+    return ValueImpl.BOOLEAN_TRUTHY_VALUES.indexOf(this.value) >= 0;
+  }
+  asNumber(): number {
+    const num = Number(this.value);
+    if (isNaN(num)) {
+      return ValueImpl.DEFAULT_VALUE_FOR_NUMBER;
     }
+    return num;
+  }
+  asString(): string {
+    return this.value;
   }
+  getSource(): ValueSource {
+    return this.source;
+  }
+
 }
 
 /**

test/unit/remote-config/remote-config.spec.ts

@@ -921,10 +921,9 @@ describe('RemoteConfig', () => {
         return remoteConfig.getServerTemplate()
           .then((template: ServerTemplate) => {
             const config = template.evaluate!();
-            expect(config.dog_type).to.equal('corgi');
-            expect(config.dog_type_enabled).to.equal(true);
-            expect(config.dog_age).to.equal(22);
-            expect(config.dog_jsonified).to.equal('{"name":"Taro","breed":"Corgi","age":1,"fluffiness":100}');
+            expect(config.getString('dog_type')).to.equal('corgi');
+            expect(config.getBoolean('dog_type_enabled')).to.equal(true);
+            expect(config.getNumber('dog_age')).to.equal(22);
           });
       });
 
@@ -963,7 +962,7 @@ describe('RemoteConfig', () => {
           }
         });
         const config = template.evaluate();
-        expect(config.is_enabled).to.be.true;
+        expect(config.getBoolean('is_enabled')).to.be.true;
       });
 
       it('honors condition order', () => {
@@ -1025,7 +1024,7 @@ describe('RemoteConfig', () => {
           }
         });
         const config = template.evaluate();
-        expect(config.dog_type).to.eq('corgi');
+        expect(config.getString('dog_type')).to.eq('corgi');
       });
 
       it('uses local default if parameter not in template', () => {
@@ -1040,7 +1039,7 @@ describe('RemoteConfig', () => {
         })
           .then((template: ServerTemplate) => {
             const config = template.evaluate!();
-            expect(config.dog_coat).to.equal(template.defaultConfig.dog_coat);
+            expect(config.getString('dog_coat')).to.equal(template.defaultConfig.dog_coat);
           });
       });
 
@@ -1056,7 +1055,8 @@ describe('RemoteConfig', () => {
         })
           .then((template: ServerTemplate) => {
             const config = template.evaluate!();
-            expect(config.dog_no_remote_default_value).to.equal(template.defaultConfig.dog_no_remote_default_value);
+            expect(config.getString('dog_no_remote_default_value')).to.equal(
+              template.defaultConfig.dog_no_remote_default_value);
           });
       });
 
@@ -1072,7 +1072,8 @@ describe('RemoteConfig', () => {
         })
           .then((template: ServerTemplate) => {
             const config = template.evaluate!();
-            expect(config.dog_use_inapp_default).to.equal(template.defaultConfig.dog_use_inapp_default);
+            expect(config.getString('dog_use_inapp_default')).to.equal(
+              template.defaultConfig.dog_use_inapp_default);
           });
       });
 
@@ -1102,7 +1103,7 @@ describe('RemoteConfig', () => {
 
         let config = template.evaluate();
 
-        expect(config.dog_type).to.equal('pug');
+        expect(config.getString('dog_type')).to.equal('pug');
 
         response.parameters = {
           dog_type: {
@@ -1117,7 +1118,7 @@ describe('RemoteConfig', () => {
 
         config = template.evaluate();
 
-        expect(config.dog_type).to.equal('corgi');
+        expect(config.getString('dog_type')).to.equal('corgi');
       });
 
       it('overrides local default when remote value exists', () => {
@@ -1146,7 +1147,7 @@ describe('RemoteConfig', () => {
           .then((template: ServerTemplate) => {
             const config = template.evaluate();
             // Asserts remote value overrides local default.
-            expect(config.dog_type_enabled).to.be.true;
+            expect(config.getBoolean('dog_type_enabled')).to.be.true;
           });
       });
     });