Support full & basic parsing 🎉

src/cashify.ts

@@ -1,5 +1,6 @@
 import {Options} from './lib/options';
 import convert from './convert';
+import parse from './utils/parser';
 
 export default class Cashify {
 	constructor(public readonly options: Partial<Options>) { }
@@ -10,12 +11,11 @@ export default class Cashify {
 	* @return Conversion result.
 	*/
 	convert(amount: number | string, options?: Partial<Options>): number {
-		// If provided `amount` is a string, get the right amount and detect the `from` currency
+		// If provided `amount` is a string, use parsing
 		if (typeof amount === 'string') {
-			const from = amount.replace(/(?<currency_code>[^A-Za-z])/g, '');
-			amount = parseFloat(amount.replace(/[^0-9-.]/g, ''));
+			const data = parse(amount);
 
-			return convert(amount, {...this.options, from, ...options} as Options);
+			return convert(data.amount, {...this.options, from: data.from, to: data.to, ...options} as Options);
 		}
 
 		return convert(amount, {...this.options, ...options} as Options);

src/convert.ts

@@ -1,18 +1,18 @@
 import getRate from './lib/get-rate';
 import {Options} from './lib/options';
+import parse from './utils/parser';
 
 /**
 * @param amount Amount of money you want to convert.
 * @param options Conversion options.
 * @return Conversion result.
 */
 export default function convert(amount: number | string, {from, to, base, rates}: Options): number {
-	// If provided `amount` is a string, get the right amount and detect the `from` currency
+	// If provided `amount` is a string, use parsing
 	if (typeof amount === 'string') {
-		from = amount.replace(/(?<currency_code>[^A-Za-z])/g, '');
-		amount = parseFloat(amount.replace(/[^0-9-.]/g, ''));
+		const data = parse(amount);
 
-		return (amount * 100) * getRate(base, rates, from, to) / 100;
+		return (data.amount * 100) * getRate(base, rates, data.from ?? from, data.to ?? to) / 100;
 	}
 
 	return (amount * 100) * getRate(base, rates, from, to) / 100;

src/utils/parser.ts

@@ -0,0 +1,36 @@
+interface Options {
+	amount: number;
+	from: string | undefined;
+	to: string | undefined;
+}
+
+/**
+* Expression parser
+* @param expression Expression you want to parse, ex. `10 usd to pln` or `€1.23 eur`
+* @return Object with parsing results
+*/
+export default function parse(expression: string): Options {
+	const amount = parseFloat(expression.replace(/[^0-9-.]/g, '')) || undefined;
+	let from;
+	let to;
+
+	// Search for `to` keyword (case insensitive) to split the expression into 2 parts
+	if (/to/i.exec(expression)) {
+		const firstPart = expression.slice(0, expression.search(/to/i)).toUpperCase().trim();
+
+		from = firstPart.replace(/(?<currency_code>[^A-Za-z])/g, '');
+		to = expression.slice(expression.search(/to/i) + 2).toUpperCase().trim();
+	} else {
+		from = expression.replace(/(?<currency_code>[^A-Za-z])/g, '');
+	}
+
+	if (amount === undefined) {
+		throw new Error('Could not parse the `amount` argument. Make sure it includes at least a valid amount.');
+	}
+
+	return {
+		amount,
+		from: from.toUpperCase() || undefined,
+		to
+	};
+}