Merge pull request #253 from mrodrig/feat/excludeKeys-regexp-support

RegExp support for excludeKeys

Author: mrodrig

README.md

@@ -87,7 +87,7 @@ Returns the CSV `string` or rejects with an `Error` if there was an issue.
       ```
     * Note: This may result in CSV output that does not map back exactly to the original JSON.
   * `excelBOM` - Boolean - Should a unicode character be prepended to allow Excel to open a UTF-8 encoded file with non-ASCII characters present.
-  * `excludeKeys` - Array - Specify the keys that should be excluded from the output. Provided keys will also be used as a RegExp to help exclude keys under a specified prefix, such as all keys of Objects in an Array when `expandArrayObjects` is `true`.
+  * `excludeKeys` - Array - Specify the `string` keys or `RegExp` patterns that should be excluded from the output. Provided `string` keys will also be used as a RegExp to help exclude keys under a specified prefix, such as all keys of Objects in an Array when `expandArrayObjects` is `true` (e.g., providing `'baz'` will exclude `'baz.a'` too).
     * Default: `[]`
     * Note: When used with `unwindArrays`, arrays present at excluded key paths will not be unwound.
   * `expandNestedObjects` - Boolean - Should nested objects be deep-converted to CSV?

src/json2csv.ts

@@ -85,7 +85,7 @@ export const Json2Csv = function(options: FullJson2CsvOptions) {
             return keyPaths.filter((keyPath) => {
                 for (const excludedKey of options.excludeKeys) {
                     // Only match if the excludedKey appears at the beginning of the string so we don't accidentally match a key farther down in a key path
-                    const regex = new RegExp(`^${excludedKey}`);
+                    const regex = excludedKey instanceof RegExp ? excludedKey : new RegExp(`^${excludedKey}`);
 
                     if (excludedKey === keyPath || keyPath.match(regex)) {
                         return false; // Exclude the key

src/types.ts

@@ -155,7 +155,7 @@ export interface Json2CsvOptions extends SharedConverterOptions {
   /**
    * Specify the keys that should be excluded from the output.
    */
-  excludeKeys?: string[];
+  excludeKeys?: (string | RegExp)[];
 
   /**
    * Specify how values should be converted into CSV format. This function is provided a single field value at a time and must return a `String`.

test/json2csv.ts

@@ -578,6 +578,26 @@ export function runTests() {
                 assert.equal(csv, updatedCsv);
             });
 
+            // Test case for #252
+            it('should exclude a single key that matches a provided excludeKeys RegExp', () => {
+                const updatedCsv = csvTestData.wildcardMatch.replace(',baz.array', ',baz.b').replace(',c', ',b');
+
+                const csv = json2csv(jsonTestData.wildcardMatch, {
+                    excludeKeys: [/array/],
+                });
+                assert.equal(csv, updatedCsv);
+            });
+
+            // Test case for #252
+            it('should exclude multiple keys that match a provided excludeKeys RegExp', () => {
+                const updatedCsv = csvTestData.wildcardMatch.replace(',baz.a,baz.array', '').replace(',a,c', '');
+
+                const csv = json2csv(jsonTestData.wildcardMatch, {
+                    excludeKeys: [/baz/],
+                });
+                assert.equal(csv, updatedCsv);
+            });
+
             // Test case for #207
             it('should include the array indexes in CSV key headers if specified via the option', () => {
                 const csv = json2csv(jsonTestData.arrayIndexesAsKeys, {