Merge pull request #15 from Balastrong/support-bracket-notation

feat: support bracket notation for arrays

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to the library will be documented in this file.
 
+## vX.X.X (Month DD, YYYY)
+
+- Add support for array bracket notation (pull request #15)
+
 ## v0.7.5 (June 01, 2024)
 
 - Republish previous version because build step was forgotten

README.md

@@ -31,7 +31,9 @@ import { decode } from 'https://deno.land/x/decode_formdata/mod.ts';
 
 `FormData` stores the names of your fields and their values. However, there is a problem. Only strings and files are accepted as values, but complex forms can contain booleans, strings and dates. This leads to the fact that the boolean value `true` must be mapped with `"on"` and `false` values are simply ignored. Numbers and dates are also converted to strings.
 
-Another problem are objects and arrays, which are usually mapped using dot notation. For example, the input field `<input name="todos.0.label" />` should map to the object `{ todos: [{ label: "" }] }`. By telling `decode` where arrays, booleans, dates, files, and numbers are located, the function can decode your `FormData` back into a complex JavaScript object.
+Another problem are objects and arrays, which are usually mapped using dot and bracket notation. For example, the input field `<input name="todos.0.label" />` should map to the object `{ todos: [{ label: "" }] }`. By telling `decode` where arrays, booleans, dates, files, and numbers are located, the function can decode your `FormData` back into a complex JavaScript object.
+
+> Both dot and bracket notation are supported for arrays.
 
 Consider the following form to add a new product to an online store:
 
@@ -174,3 +176,7 @@ Find a bug or have an idea how to improve the library? Please fill out an [issue
 ## License
 
 This project is available free of charge and licensed under the [MIT license](https://github.com/fabian-hiller/decode-formdata/blob/main/LICENSE.md).
+
+## Note
+
+Both dot and bracket notation are supported for arrays.

src/decode.test.ts

@@ -64,7 +64,7 @@ describe('decode', () => {
     expect(decode(formData, { files: ['file'] })).toEqual({ file });
   });
 
-  test('should decode indexed arrays', () => {
+  test('should decode indexed arrays with dot notation', () => {
     const formData = new FormData();
     formData.append('array.0', 'index_0');
     formData.append('array.1', 'index_1');
@@ -74,6 +74,16 @@ describe('decode', () => {
     });
   });
 
+  test('should decode indexed arrays with bracket notation', () => {
+    const formData = new FormData();
+    formData.append('array[0]', 'index_0');
+    formData.append('array[1]', 'index_1');
+    formData.append('array[2]', 'index_2');
+    expect(decode(formData, { arrays: ['array'] })).toEqual({
+      array: ['index_0', 'index_1', 'index_2'],
+    });
+  });
+
   test('should decode non-indexed arrays', () => {
     const formData = new FormData();
     formData.append('array', 'index_0');
@@ -88,7 +98,7 @@ describe('decode', () => {
     });
   });
 
-  test('should decode numbers in array', () => {
+  test('should decode numbers in array with dot notation', () => {
     const formData = new FormData();
     formData.append('array.0', '111');
     formData.append('array.1', '222');
@@ -100,6 +110,18 @@ describe('decode', () => {
     });
   });
 
+  test('should decode numbers in array with bracket notation', () => {
+    const formData = new FormData();
+    formData.append('array[0]', '111');
+    formData.append('array[1]', '222');
+    formData.append('array[2]', '333');
+    expect(
+      decode(formData, { arrays: ['array'], numbers: ['array[$]'] })
+    ).toEqual({
+      array: [111, 222, 333],
+    });
+  });
+
   test('should decode objects', () => {
     const formData = new FormData();
     formData.append('nested.string', 'hello');
@@ -108,7 +130,7 @@ describe('decode', () => {
     });
   });
 
-  test('should decode nested arrays', () => {
+  test('should decode nested arrays with dot notation', () => {
     const formData = new FormData();
     formData.append('nested.0.array.0', 'index_0');
     formData.append('nested.0.array.1', 'index_1');
@@ -123,6 +145,21 @@ describe('decode', () => {
     });
   });
 
+  test('should decode nested arrays with bracket notation', () => {
+    const formData = new FormData();
+    formData.append('nested[0].array[0]', 'index_0');
+    formData.append('nested[0].array[1]', 'index_1');
+    formData.append('nested[0].array[2]', 'index_2');
+    expect(
+      decode(formData, {
+        arrays: ['nested[$].array', 'empty.array'],
+      })
+    ).toEqual({
+      nested: [{ array: ['index_0', 'index_1', 'index_2'] }],
+      empty: { array: [] },
+    });
+  });
+
   test('should transform value', () => {
     const formData = new FormData();
     formData.append('string', 'hello');

src/decode.ts

@@ -43,19 +43,39 @@ export function decode<
   const [info, transform] =
     typeof arg2 === 'function' ? [undefined, arg2] : [arg2, arg3];
 
+  // Normalize info arrays to dot notation
+  if (info) {
+    for (const key of [
+      'arrays',
+      'booleans',
+      'dates',
+      'files',
+      'numbers',
+    ] as const) {
+      if (info[key]?.length) {
+        info[key] = info[key]!.map((templateName) =>
+          templateName.replace(/\[\$\]/g, '.$')
+        );
+      }
+    }
+  }
+
   // Create empty values object
   const values: any = {};
 
   // Add each form entry to values
   for (const [path, input] of formData.entries()) {
+    // Normalize path to dot notation
+    const normlizedPath = path.replace(/\[(\d+)\]/g, '.$1');
+
     // Create template name and keys
-    const templateName = path
+    const templateName = normlizedPath
       .replace(/\.\d+\./g, '.$.')
       .replace(/\.\d+$/, '.$');
     const templateKeys = templateName.split('.');
 
     // Add value of current field to values
-    path.split('.').reduce((object, key, index, keys) => {
+    normlizedPath.split('.').reduce((object, key, index, keys) => {
       // If it is not last index, return array or object
       if (index < keys.length - 1) {
         // If array or object already exists, return it