fix issue 210: custom values formatting schema

index.d.ts

@@ -1,3 +1,5 @@
+export type CustomValueParser = (value: string) => any;
+
 export interface ParseOptions {
 	/**
 	Decode the keys and values. URI components are decoded with [`decode-uri-component`](https://github.com/SamVerschueren/decode-uri-component).
@@ -121,6 +123,23 @@ export interface ParseOptions {
 	```
 	*/
 	readonly parseBooleans?: boolean;
+
+	/**
+	Parse the value as a boolean type instead of string type if it's a boolean.
+
+	@default false
+
+	@example
+	```
+	import queryString = require('query-string');
+
+	queryString.parse('foo=true', {parseBooleans: true});
+	//=> {foo: true}
+	```
+	*/
+	readonly types?: {
+		[key: string]: 'string' | 'number' | CustomValueParser;
+	};
 }
 
 export interface ParsedQuery<T = string> {

index.js

@@ -64,62 +64,90 @@ function encoderForArrayFormat(options) {
 	}
 }
 
+function createCustomValueParser(typedSchemaFormatter) {
+	if (typedSchemaFormatter === 'string') {
+		return String;
+	}
+
+	if (typedSchemaFormatter === 'number') {
+		return Number;
+	}
+
+	if (typeof typedSchemaFormatter === 'function') {
+		return typedSchemaFormatter;
+	}
+
+	return val => val;
+}
+
+function getPreparedValue(typesSchema, key, value) {
+	const customValueParser = createCustomValueParser(typesSchema[key]);
+	return customValueParser(value);
+}
+
 function parserForArrayFormat(options) {
 	let result;
 
 	switch (options.arrayFormat) {
 		case 'index':
 			return (key, value, accumulator) => {
+				const preparedValue = getPreparedValue(options.types, key, value);
+
 				result = /\[(\d*)\]$/.exec(key);
 
 				key = key.replace(/\[\d*\]$/, '');
 
 				if (!result) {
-					accumulator[key] = value;
+					accumulator[key] = preparedValue;
 					return;
 				}
 
 				if (accumulator[key] === undefined) {
 					accumulator[key] = {};
 				}
 
-				accumulator[key][result[1]] = value;
+				accumulator[key][result[1]] = preparedValue;
 			};
 
 		case 'bracket':
 			return (key, value, accumulator) => {
+				const preparedValue = getPreparedValue(options.types, key, value);
+
 				result = /(\[\])$/.exec(key);
 				key = key.replace(/\[\]$/, '');
 
 				if (!result) {
-					accumulator[key] = value;
+					accumulator[key] = preparedValue;
 					return;
 				}
 
 				if (accumulator[key] === undefined) {
-					accumulator[key] = [value];
+					accumulator[key] = [preparedValue];
 					return;
 				}
 
-				accumulator[key] = [].concat(accumulator[key], value);
+				accumulator[key] = [].concat(accumulator[key], preparedValue);
 			};
 
 		case 'comma':
 		case 'separator':
 			return (key, value, accumulator) => {
 				const isArray = typeof value === 'string' && value.split('').indexOf(options.arrayFormatSeparator) > -1;
 				const newValue = isArray ? value.split(options.arrayFormatSeparator).map(item => decode(item, options)) : value === null ? value : decode(value, options);
-				accumulator[key] = newValue;
+				const preparedValue = getPreparedValue(options.types, key, newValue);
+				accumulator[key] = preparedValue;
 			};
 
 		default:
 			return (key, value, accumulator) => {
+				const preparedValue = getPreparedValue(options.types, key, value);
+
 				if (accumulator[key] === undefined) {
-					accumulator[key] = value;
+					accumulator[key] = preparedValue;
 					return;
 				}
 
-				accumulator[key] = [].concat(accumulator[key], value);
+				accumulator[key] = [].concat(accumulator[key], preparedValue);
 			};
 	}
 }
@@ -206,7 +234,8 @@ function parse(input, options) {
 		arrayFormat: 'none',
 		arrayFormatSeparator: ',',
 		parseNumbers: false,
-		parseBooleans: false
+		parseBooleans: false,
+		types: Object.create(null)
 	}, options);
 
 	validateArrayFormatSeparator(options.arrayFormatSeparator);
@@ -250,7 +279,9 @@ function parse(input, options) {
 		return ret;
 	}
 
-	return (options.sort === true ? Object.keys(ret).sort() : Object.keys(ret).sort(options.sort)).reduce((result, key) => {
+	const retKeys = options.sort === true ? Object.keys(ret).sort() : Object.keys(ret).sort(options.sort);
+
+	return retKeys.reduce((result, key) => {
 		const value = ret[key];
 		if (Boolean(value) && typeof value === 'object' && !Array.isArray(value)) {
 			// Sort object keys, not values