feat(lib): Make default property in Fn.lookup optional and introduce …

…Fn.lookupNested
hashicorp · Jul 27, 2023 · b9e31ac · b9e31ac
1 parent 2664dbc
commit b9e31ac
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Showing 2 changed files with 55 additions and 5 deletions.
diff --git a/packages/cdktf/lib/terraform-functions.ts b/packages/cdktf/lib/terraform-functions.ts
@@ -1,6 +1,6 @@
 // Copyright (c) HashiCorp, Inc
 // SPDX-License-Identifier: MPL-2.0
-import { rawString, Token } from ".";
+import { propertyAccess, rawString, Token } from ".";
 import { FnGenerated } from "./functions/terraform-functions.generated";
 
 // eslint-disable-next-line jsdoc/require-jsdoc
@@ -21,12 +21,22 @@ export class Fn extends FnGenerated {
    * {@link /terraform/docs/language/functions/lookup.html lookup} retrieves the value of a single element from a map, given its key. If the given key does not exist, the given default value is returned instead.
    * @param {any} inputMap
    * @param {string} key
-   * @param {Array<any>} defaultValue
+   * @param {any} [defaultValue]
    */
-  static lookup(inputMap: any, key: string, defaultValue: any) {
+  static lookup(inputMap: any, key: string, defaultValue?: any) {
     // overwritten because lookup() uses a variadic argument for its optional defaultValue
-    // we don't model it as optional since not passing it is deprecated in favor of the native Terraform expression "inputMap[key]"
-    return Fn._lookup(inputMap, key, [defaultValue]);
+    if (defaultValue) return Fn._lookup(inputMap, key, [defaultValue]);
+    return propertyAccess(inputMap, [key]); // -> renders inputMap[key] (which is recommened if no default value is given)
+  }
+
+  /**
+   * returns a property access expression that accesses the property at the given path in the given inputMap.
+   * For example lookupNested(x, ["a", "b", "c"]) will return a Terraform expression like x["a"]["b"]["c"]
+   * @param {any} inputMap
+   * @param {Array<any>} path
+   */
+  static lookupNested(inputMap: any, path: any[]) {
+    return propertyAccess(inputMap, path);
   }
 
   /**

diff --git a/packages/cdktf/test/functions.test.ts b/packages/cdktf/test/functions.test.ts
@@ -553,3 +553,43 @@ it("errors mentioning function name and argument", () => {
     `"Argument 1 of replace failed the validation: Error: 'this one " not' can not be used as value directly since it has unescaped double quotes in it. To safely use the value please use Fn.rawString on your string."`
   );
 });
+
+test("Property access using lookup and lookupNested functions", () => {
+  const app = Testing.app();
+  const stack = new TerraformStack(app, "test");
+
+  const variable = new TerraformVariable(stack, "test-var", {
+    type: `object({a = object({b = string}), z = string})`,
+  });
+
+  new TerraformOutput(stack, "lookup", {
+    value: Fn.lookup(variable.value, "z", "defaultzzzz"),
+  });
+  new TerraformOutput(stack, "native-access", {
+    value: Fn.lookup(variable.value, "z"),
+  });
+  new TerraformOutput(stack, "native-access-nested", {
+    value: Fn.lookupNested(variable.value, ["a", "b"]),
+  });
+
+  expect(Testing.synth(stack)).toMatchInlineSnapshot(`
+    "{
+      \\"output\\": {
+        \\"lookup\\": {
+          \\"value\\": \\"\${lookup(var.test-var, \\\\\\"z\\\\\\", \\\\\\"defaultzzzz\\\\\\")}\\"
+        },
+        \\"native-access\\": {
+          \\"value\\": \\"\${var.test-var[\\\\\\"z\\\\\\"]}\\"
+        },
+        \\"native-access-nested\\": {
+          \\"value\\": \\"\${var.test-var[\\\\\\"a\\\\\\"][\\\\\\"b\\\\\\"]}\\"
+        }
+      },
+      \\"variable\\": {
+        \\"test-var\\": {
+          \\"type\\": \\"object({a = object({b = string}), z = string})\\"
+        }
+      }
+    }"
+  `);
+});