fix: types made optional

fix #84

Author: bugwheels94

src/index.ts

@@ -7,7 +7,6 @@ import { createMathFunctions } from './functions'
 // var Mexp = function (parsed) {
 //   this.value = parsed
 // }
-
 class Mexp {
 	static TOKEN_TYPES = tokenTypes
 	static tokenTypes = tokenTypes
@@ -16,7 +15,7 @@ class Mexp {
 	addToken = addToken
 	lex = lex
 	postfixEval = postfixEval
-	eval(string: string, tokens: Token[], Constants: Constants) {
+	eval(string: string, tokens?: Token[], Constants?: Constants) {
 		return this.postfixEval(this.toPostfix(this.lex(string, tokens)), Constants)
 	}
 	math!: ReturnType<typeof createMathFunctions>

src/lexer.ts

@@ -195,7 +195,7 @@ function tokenize(mexp: Mexp, string: string) {
   }
   return nodes;
 }
-export const lex = function (this: Mexp, inp: string, tokens: Token[]) {
+export const lex = function (this: Mexp, inp: string, tokens?: Token[]) {
   "use strict";
   var changeSignObj: ParsedToken = {
     value: this.math.changeSign,

src/postfix_evaluator.ts

@@ -1,7 +1,7 @@
 import { toPostfix } from './postfix'
 import { tokenTypes, ParsedToken } from './token'
 export type Constants = Record<string, number>
-export function postfixEval(arr: ReturnType<typeof toPostfix>, Constants: Constants) {
+export function postfixEval(arr: ReturnType<typeof toPostfix>, Constants?: Constants) {
 	Constants = Constants || {}
 	Constants.PI = Math.PI
 	Constants.E = Math.E