ViewPoint is a math expression parser and evaluator that supports runtime data-type checking written in native JS. It allows you to evaluate mathematical expressions with ease while ensuring the correctness of the input data.
- Expression Evaluation:
- Parses and evaluates mathematical expressions like '5*52+285/2'
- Supports basic arithmetic operators (+, -, *, /,^, %). [Note: here % is implemented as modules / reminder operator]
- Supports nested expressions with parentheses (e.g. (36/2)-4)
- Allows complex expressions with multiple levels of nesting (e.g (52/8+2)+56*((25/2)*4+(8-2))
- Supports multiple datatypes e.g expressions with decimal / floating points numbers, BigInt, String, and Boolean datatype
- Data Type Validation:
- Validates data types during expression evaluation, throwing errors for invalid operations (e.g., attempting sum or multiplication between strings and numbers).
- Expression Tokenization:
- It can tokenize a mathematical expression into individual tokens and can return tokenized expression as an array (e.g expression = "5 + 72+(85^2+1)", token = [5,'+',7,'',2,'+','(',85,'^',2,'+',1,')'])
- Infix to Postfix Conversion:
- It can convert infix expressions to postfix notation and return as an array
- JavaScript Variable Support:
- ViewPoint supports using of JavaScript variables in an expressions using
${}and backticks (`)
- ViewPoint supports using of JavaScript variables in an expressions using
- External Variable Support:
- Allows users to define external variables using the
.var()method
- Allows users to define external variables using the
- Operator Order Control:
- Follows PEMDAS (Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction) order of operations by default
- Allows users to define their own custom order of operations (if needed)
- Customizable Operator Behavior:
- Allows users to re-define the math operator (e.g. '*' or '%') behavior to suit specific requirements (if needed)
To use this evaluator/library, firstly, you need to link ViewPoint.js to your project. You can do that by using two ways:
- Download/Clone and Use: Download or clone the repository and use the ViewPoint.js file in your project.
- Use via CDN:
- Use the library directly via CDN using the following script tag:
https://cdn.jsdelivr.net/gh/nirmalpaul383/ViewPoint/ViewPoint.js - For using it in browser/webpage you can use
<script src="https://cdn.jsdelivr.net/gh/nirmalpaul383/ViewPoint/ViewPoint.js"></script>
- Use the library directly via CDN using the following script tag:
- create a ViewPoint object using
new ViewPoint()keywords:
//Create a new ViewPoint object with ViewPoint class let ViewPoint_obj = new ViewPoint();- Store your expression in string format:
//Sample Expression const expresion = `((52/8+2)+56*((25/2)*4+(8-2)))*2`;- For evaluating an expression use
.evaluate()method:
//Expression evaluating let output = ViewPoint_obj.evaluate(expresion); //For output console.log(output); //Output 6289 to the console//Create a new ViewPoint object with ViewPoint class let ViewPoint_obj = new ViewPoint(); //Simple Expression evaluation console.log(ViewPoint_obj.evaluate(`25+5*2`)); //Output 35 to the console //Nested expression evaluation console.log(ViewPoint_obj.evaluate(`((52/8+2)+56*((25/2)*4+(8-2)))*2`)); //Output 6289 to the console //BigInt Expression evaluation console.log(ViewPoint_obj.evaluate(`11n ^2n`)); //Output 121n to the console //String concatenation: '+' Operator behaves as concatenation operator if all operands are string console.log(ViewPoint_obj.evaluate(`"Hello " + "World"`)); //Output "Hello World" to the console //Invalid Expression: One operand is a string and another one is number console.log(ViewPoint_obj.evaluate(`"45" + 5`)); //Throws a datatype error //Invalid Expression: One operand is a number and another one is boolean console.log(ViewPoint_obj.evaluate(`45 * true`)); //Throws a datatype error //Invalid Expression: unclosed quoted text console.log(ViewPoint_obj.evaluate(`"Hello World `)); //Throws a error message for unclosed quoted text//Create a new ViewPoint object with the viewpoint class let ViewPoint_obj = new ViewPoint(); //Sample expression with number, operators, BigInt, parentheses, floating point number, quoted text, and white space const expresion = `2 / 5.04 +5n +"Sample quoted text" + (40*(45-2))`; //For tokenization of expression and storing into the token array let token_array = ViewPoint_obj.tokenize(expresion) //For output the token array into the console console.log(token_array) /* [ 2, '/', 5.04, '+', 5n, '+', 'Sample quoted text', '+', '(', 40, '\*', '(', 45, '-', 2, ')', ')' ] *///Create a new ViewPoint object with viewpoint class let VP = new ViewPoint(); //Sample expression const expresion = `4+8*(5-1)`; //For tokenization of expression and storing into the token array let token_array = VP.tokenize(expresion) //For converting an infix expression array to its equivalent postfix expression array and storing into the postfix array let postFix_Array = VP.infix_to_postfix(...token_array) //For output the postfix expression array into the console console.log(postFix_Array) //Output: [ 4, 8, 5, 1, '-', '*', '+' ]//Create a new ViewPoint object with the ViewPoint class let VP = new ViewPoint(); //Sample JavaScript variable let a = 5; //Sample expression with JavaScript variable const expresion = `35 +(${a}*9)*2`; //Expression evaluating and storing the result into the output variable let output = VP.evaluate(expresion); //For output the result console.log(output); //Output: 125//Create a new ViewPoint object with viewpoint class let ViewPoint_obj = new ViewPoint(); //Defining external variable with the name of "myVar" ViewPoint_obj.var("myVar", 400); //Sample expression with an external variable const expresion = `35 *100 - myVar`; //Expression evaluating and storing the result into the output variable let output = ViewPoint_obj.evaluate(expresion); //For output the result console.log(output); //Output: 3100//Create a new ViewPoint object with viewpoint class let ViewPoint_obj = new ViewPoint(); //Sample expression const expresion = `4*2+1`; //Expression evaluating with default operator precedence let output = ViewPoint_obj.evaluate(expresion); //Changing the default operator_precedence in the ViewPoint Obejct //promote '+' and '-' operator to highest precedence ViewPoint_obj.ViewPoint_math_def.operator_precedence = { '^': 1, '*': 1, '/': 1, '%': 1, '+': 2, '-': 2, } //Expression re-evaluating let output2 = ViewPoint_obj.evaluate(expresion); //For output the actual result console.log(output); //Output: 9 (First * then +) //For output the re-evaluating result (after changing the default operator_precedence) console.log(output2); //Output: 12 (First + then *)//Create a new ViewPoint object with viewpoint class let ViewPoint_obj = new ViewPoint(); //Sample expression const expresion = `4*2`; //Expression evaluating with default operator behavior let output = ViewPoint_obj.evaluate(expresion); //Override default behavior of multiplication ('*') operator in the ViewPoint object and redefine * operator to behave like '+' (addition) operator ViewPoint_obj.ViewPoint_math_def.multiplication = function (val1, val2) { return val1 + val2; } //Expression re-evaluating let output2 = ViewPoint_obj.evaluate(expresion); //For output the actual result console.log(output); //Output: 8 (multiplication ('*') operator works as multiplication) //For output the re-evaluating result (multiplication ('*') operator works as addition ('+')) console.log(output2); //Output: 6This object is used for defining of some basic math logic and math operations for ViewPoint
| Name | Type | Details |
|---|---|---|
| operator_precedence | Object | This object contains the operator's precedence value according to the BODMAS or PEMDAS rule Default operator's precedence values: operator_precedence: {'^': 4, '*': 3, '/': 2, '%': 2,'+': 1,'-': 1} |
| exponents(value1, value2) | Method | Definition of Power(^) operator Behavior |
| multiplication(value1, value2) | Method | Definition of Multiplication(*) operator Behavior |
| division(value1, value2) | Method | Definition of Division(/) operator Behavior |
| modulus(value1, value2) | Method | Definition of Modulus(%) operator Behavior |
| addition(value1, value2) | Method | Definition of Addition(+) and concatenation(+) operator Behavior |
| subtraction(value1, value2) | Method | Definition of Subtraction(-) operator Behavior |
If you like this project please give a star to this project . This project is originally made by me(N Paul). My github profile , My youtube page , facebook page
This is an open-source program. You are welcome to modify it...
Thank you for trying it out!