feat(prettier-plugin-jsdoc): add function to format TS types

src/fns/formatTSTypes.js

@@ -0,0 +1,57 @@
+const R = require('ramda');
+const { capitalize, ensureArray } = require('./utils');
+
+/**
+ * Utility function generated by {@link getFormater} and that can be used to modify a type name.
+ * The difference between the formatter and the modifier is that the formatter can extract single
+ * types from a comple type and run them through the modifier, where the modifier can only handle
+ * one type.
+ *
+ * @callback TypeFormatter
+ * @param {string} type  The original type.
+ * @returns {string}
+ */
+
+/**
+ * Utility function that is sent to {@link getFormatter} and that the formatter will use to modify
+ * each single type name referenced on the given type.
+ *
+ * @callback TypeModifier
+ * @param {string} type  The original type.
+ * @returns {string}
+ */
+
+/**
+ * Generates a formatter function that will replace a type (or types) after sending it through
+ * a modification function.
+ *
+ * @param {string|string[]} type      The type or types to format.
+ * @param {TypeModifier}    modifier  The function that will modify each type.
+ * @returns {TypeFormatter}
+ */
+const getFormater = (type, modifier) => R.compose(
+  (types) => R.replace(
+    new RegExp(`([^\\w]|^)(${types})([^\\w]|$)`, 'g'),
+    (_, before, rawType, after) => `${before}${modifier(rawType)}${after}`,
+  ),
+  R.join('|'),
+  ensureArray,
+)(type);
+
+/**
+ * Formats each type reference on a type in order to match the casing allowed by TypeScript.
+ *
+ * @callback FormatTSTypesFn
+ * @param {string} type  The type to format.
+ * @returns {string}
+ */
+
+/**
+ * @type {FormatTSTypesFn}
+ */
+const formatTSTypes = R.compose(
+  getFormater(['array', 'object'], capitalize),
+  getFormater(['String', 'Number', 'Boolean'], R.toLower),
+);
+
+module.exports.formatTSTypes = formatTSTypes;

src/fns/utils.js

@@ -147,6 +147,22 @@ const replaceDotOnTypeGeneric = R.curry((targetType, useDot, type) => R.ifElse(
   R.replace(new RegExp(`([^\\w]|^)${targetType}\\s*\\.\\s*<`, 'g'), `$1${targetType}<`),
 )(type));
 
+/**
+ * Capitalizes a string.
+ *
+ * @callback CapitalizeFn
+ * @param {string} str  The string to capitalize.
+ * @returns {string}
+ */
+
+/**
+ * @type {CapitalizeFn}
+ */
+const capitalize = R.compose(
+  R.join(''),
+  R.juxt([R.compose(R.toUpper, R.head), R.tail]),
+);
+
 module.exports.ensureArray = ensureArray;
 module.exports.findTagIndex = findTagIndex;
 module.exports.appendIfNotPresent = appendIfNotPresent;
@@ -155,3 +171,4 @@ module.exports.replaceLastItem = replaceLastItem;
 module.exports.hasItems = hasItems;
 module.exports.isMatch = isMatch;
 module.exports.replaceDotOnTypeGeneric = replaceDotOnTypeGeneric;
+module.exports.capitalize = capitalize;

test/fns/formatTSTypes.test.js

@@ -0,0 +1,29 @@
+jest.unmock('../../src/fns/formatTSTypes');
+jest.unmock('../../src/fns/utils');
+
+const { formatTSTypes } = require('../../src/fns/formatTSTypes');
+
+describe('formatTSTypes', () => {
+  it
+  .each([
+    ['String', 'string'],
+    ['string', 'string'],
+    ['Number', 'number'],
+    ['number', 'number'],
+    ['Boolean', 'boolean'],
+    ['boolean', 'boolean'],
+    ['Array', 'Array'],
+    ['array', 'Array'],
+    ['Object', 'Object'],
+    ['object', 'Object'],
+    ['otherType', 'otherType'],
+    ['OtherType', 'OtherType'],
+  ])('should transform \'%s\' into \'%s\'', (input, output) => {
+    // Given
+    let result = null;
+    // When
+    result = formatTSTypes(input);
+    // Then
+    expect(result).toBe(output);
+  });
+});