allow user to rename individual field headers

README.md

@@ -129,6 +129,9 @@ Returns the CSV `string` or rejects with an `Error` if there was an issue.
   	* `false` uses the following keys:
   		* `['specifications']`
     * Note: This may result in CSV output that does not map back exactly to the original JSON. See #102 for more information.
+  * `fieldTitleMap` - Object - Specify field titles that should be renamed.
+    * Default: `{}`
+    * Example: `{ "key1": "Key 1", "key2": "Key 2"}`
   * `keys` - Array - Specify the keys that should be converted.
     * Default: These will be auto-detected from your data by default.
     * Keys can either be specified as a String representing the key path that should be converted, or as an Object of the following format:

src/constants.ts

@@ -40,6 +40,7 @@ export const defaultJson2CsvOptions: DefaultJson2CsvOptions = {
     useDateIso8601Format: false,
     useLocaleFormat: false,
     wrapBooleans: false,
+    fieldTitleMap: Object.create({}),
 };
 
 export const defaultCsv2JsonOptions: DefaultCsv2JsonOptions = {

src/json2csv.ts

@@ -4,9 +4,9 @@ import { evaluatePath } from 'doc-path';
 import { deepKeysFromList } from 'deeks';
 import { excelBOM, errors } from './constants';
 import * as utils from './utils';
-import type { FullJson2CsvOptions, Json2CsvParams } from './types';
+import type { DefaultJson2CsvOptions, Json2CsvParams } from './types';
 
-export const Json2Csv = function (options: FullJson2CsvOptions) {
+export const Json2Csv = function (options: DefaultJson2CsvOptions) {
     const wrapDelimiterCheckRegex = new RegExp(options.delimiter.wrap, 'g'),
         crlfSearchRegex = /\r?\n|\r/,
         customValueParser = options.parseValue && typeof options.parseValue === 'function' ? options.parseValue : null,

src/types.ts

@@ -157,6 +157,11 @@ export interface Json2CsvOptions extends SharedConverterOptions {
    */
   excludeKeys?: (string | RegExp)[];
 
+  /**
+   * Map keys to user provided titles.
+   */
+  fieldTitleMap?: Record<string, string>;
+
   /**
    * 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`.
    * Note: Using this option may override other options, including `useDateIso8601Format` and `useLocaleFormat`.
@@ -189,13 +194,6 @@ export interface DefaultCsv2JsonOptions extends
   // Then extend the types with required fields and specific fields omitted:
   Omit<Omit<Omit<Omit<BuiltCsv2JsonOptions, 'wrapBooleans'>, 'keys'>, 'headerFields'>, 'parseValue'> {}
 
-export interface FullJson2CsvOptions extends DefaultJson2CsvOptions {
-  /**
-   * Internal field that is used to map keys to user provided titles.
-   */
-  fieldTitleMap: Record<string, string>;
-}
-
 export type FullCsv2JsonOptions = DefaultCsv2JsonOptions
 
 export interface HeaderField {

src/utils.ts

@@ -2,7 +2,7 @@
 
 import { evaluatePath, setPath } from 'doc-path';
 import { defaultJson2CsvOptions, defaultCsv2JsonOptions } from './constants';
-import type { Json2CsvOptions, Csv2JsonOptions, FullJson2CsvOptions, FullCsv2JsonOptions } from './types';
+import type { Json2CsvOptions, Csv2JsonOptions, DefaultJson2CsvOptions, FullCsv2JsonOptions } from './types';
 
 const dateStringRegex = /\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z/,
     MAX_ARRAY_LENGTH = 100000;
@@ -12,7 +12,7 @@ const dateStringRegex = /\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z/,
  * If a user does not provide custom options, then we use our default
  * If options are provided, then we set each valid key that was passed
  */
-export function buildJ2COptions(opts: Json2CsvOptions): FullJson2CsvOptions {
+export function buildJ2COptions(opts: Json2CsvOptions): DefaultJson2CsvOptions {
     return {
         ...defaultJson2CsvOptions,
         ...opts,
@@ -21,7 +21,7 @@ export function buildJ2COptions(opts: Json2CsvOptions): FullJson2CsvOptions {
             wrap: opts?.delimiter?.wrap || defaultJson2CsvOptions.delimiter.wrap,
             eol: opts?.delimiter?.eol || defaultJson2CsvOptions.delimiter.eol,
         },
-        fieldTitleMap: Object.create({}),
+        fieldTitleMap: opts?.fieldTitleMap || Object.create({}),
     };
 }
 
@@ -60,7 +60,7 @@ export function deepCopy<T>(obj: T): T {
  *   of a string. Given the RFC4180 requirements, that means that the value is
  *   wrapped in value wrap delimiters (usually a quotation mark on each side).
  */
-export function isStringRepresentation(fieldValue: string, options: FullJson2CsvOptions | FullCsv2JsonOptions) {
+export function isStringRepresentation(fieldValue: string, options: DefaultJson2CsvOptions | FullCsv2JsonOptions) {
     const firstChar = fieldValue[0],
         lastIndex = fieldValue.length - 1,
         lastChar = fieldValue[lastIndex];

test/config/testCsvFilesList.ts

@@ -58,6 +58,7 @@ const csvFileConfig = [
     { key: 'arrayIndexesAsKeys', file: '../data/csv/arrayIndexesAsKeys.csv' },
     { key: 'keyWithEndingDot', file: '../data/csv/keyWithEndingDot.csv' },
     { key: 'fieldEolAtStart', file: '../data/csv/fieldEolAtStart.csv' },
+    { key: 'renamedHeaderField', file: '../data/csv/renamedHeaderField.csv' },
 ];
 
 function readCsvFile(filePath: string) {

test/data/csv/renamedHeaderField.csv

@@ -0,0 +1,3 @@
+arrayOfStrings,renamedSubField,number,isBoolean,renamedOptionalField
+"[""test1"",""test2""]",subValue,5,true,this one has it
+"[""test3"",""test4""]",subValue,7,false,null

test/json2csv.ts

@@ -794,6 +794,17 @@ export function runTests() {
                 csv = json2csv(jsonTestData.deepNestedArrays.seven_levels_deep, options);
                 assert.equal(csv, expectedCSV);
             });
+
+            it('should rename the header fields according to options', () => {
+                const csv = json2csv(jsonTestData.assortedValues, {
+                    fieldTitleMap: {
+                        'optionalField': 'renamedOptionalField',
+                        'object.subField': 'renamedSubField',
+                    },
+                });
+
+                assert.equal(csv, csvTestData.renamedHeaderField);
+            });
         });
     });