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Formula Parser Build Status Test Coverage hot-formula-parser

Library provides a Parser class that evaluates excel and mathematical formulas.


Install

A recommended way to install Formula Parser is through NPM using the following command:

$ npm install hot-formula-parser --save

Node.js:

var FormulaParser = require('hot-formula-parser').Parser;
var parser = new FormulaParser();

parser.parse('SUM(1, 6, 7)'); // It returns `Object {error: null, result: 14}`

Browser:

<script src="/node_modules/hot-formula-parser/dist/formula-parser.min.js"></script>
<script>
var parser = new formulaParser.Parser();

parser.parse('SUM(1, 6, 7)'); // It returns `Object {error: null, result: 14}`
</script>

Features

It supports:

API (methods)

var parser = new formulaParser.Parser();

.parse(expression)

Parses and evaluates provided expression. It always returns an object with result and error properties. result property always keep evaluated value. If error occurs error property will be set as:

parser.parse('(1 + 5 + (5 * 10)) / 10'); // returns `Object {error: null, result: 5.6}`
parser.parse('SUM(MY_VAR)'); // returns `Object {error: "#NAME?", result: null}`
parser.parse('1;;1'); // returns `Object {error: "#ERROR!", result: null}`

.setVariable(name, value)

Set predefined variable name which can be visible while parsing formula expression.

parser.setVariable('MY_VARIABLE', 5);
parser.setVariable('fooBar', 10);

parser.parse('(1 + MY_VARIABLE + (5 * fooBar)) / fooBar'); // returns `5.6`

.getVariable(name)

Get variable name.

parser.setVariable('fooBar', 10);

parser.getVariable('fooBar'); // returns `10`

.setFunction(name, fn)

Set custom function which can be visible while parsing formula expression.

parser.setFunction('ADD_5', function(params) {
  return params[0] + 5;
});
parser.setFunction('GET_LETTER', function(params) {
  var string = params[0];
  var index = params[1] - 1;

  return string.charAt(index);
});

parser.parse('SUM(4, ADD_5(1))'); // returns `10`
parser.parse('GET_LETTER("Some string", 3)'); // returns `m`

.getFunction(name)

Get custom function.

parser.setFunction('ADD_5', function(params) {
  return params[0] + 5;
});

parser.getFunction('ADD_5')([1]); // returns `6`

.SUPPORTED_FORMULAS

List of all supported formulas function.

require('hot-formula-parser').SUPPORTED_FORMULAS; // An array of formula names

API (hooks)

'callVariable' (name, done)

Fired while retrieving variable. If variable was defined earlier using setVariable you can overwrite it by this hook.

parser.on('callVariable', function(name, done) {
  if (name === 'foo') {
    done(Math.PI / 2);
  }
});

parser.parse('SUM(SIN(foo), COS(foo))'); // returns `1`

'callFunction' (name, params, done)

Fired while calling function. If function was defined earlier using setFunction you can overwrite it's result by this hook. You can also use this to override result of build-in formulas.

parser.on('callFunction', function(name, params, done) {
  if (name === 'ADD_5') {
    done(params[0] + 5);
  }
});

parser.parse('ADD_5(3)'); // returns `8`

'callCellValue' (cellCoord, done)

Fired while retrieving cell value by its label (eq: B3, B$3, B$3, $B$3).

parser.on('callCellValue', function(cellCoord, done) {
  // using label
  if (cellCoord.label === 'B$6') {
    done('hello');
  }
  // or using indexes
  if (cellCoord.row.index === 5 && cellCoord.row.isAbsolute && cellCoord.column.index === 1 && !cellCoord.column.isAbsolute) {
    done('hello');
  }

  if (cellCoord.label === 'C6') {
    done(0.75);
  }
});

parser.parse('B$6'); // returns `"hello"`
parser.parse('B$6&" world"'); // returns `"hello world"`
parser.parse('FISHER(C6)'); // returns `0.9729550745276566`

'callRangeValue' (startCellCoord, endCellCoord, done)

Fired while retrieving cells range value (eq: A1:B3, $A1:B$3, A$1:B$3, $A$1:$B$3).

parser.on('callRangeValue', function(startCellCoord, endCellCoord, done) {
  var data = [
    [1, 2, 3, 4, 5],
    [6, 7, 8, 9, 10],
    [11, 12, 13, 14, 15],
    [16, 17, 18, 19, 20],
  ];
  var fragment = [];

  for (var row = startCellCoord.row.index; row <= endCellCoord.row.index; row++) {
    var rowData = data[row];
    var colFragment = [];

    for (var col = startCellCoord.column.index; col <= endCellCoord.column.index; col++) {
      colFragment.push(rowData[col]);
    }
    fragment.push(colFragment);
  }

  if (fragment) {
    done(fragment);
  }
});

parser.parse('JOIN(A1:E2)'); // returns `"1,2,3,4,5,6,7,8,9,10"`
parser.parse('COLUMNS(A1:E2)'); // returns `5`
parser.parse('ROWS(A1:E2)'); // returns `2`
parser.parse('COUNT(A1:E2)'); // returns `10`
parser.parse('COUNTIF(A1:E2, ">5")'); // returns `5`

Want to help?

Please see CONTRIBUTING.md.

Changelog

To see the list of recent changes, see Releases section.

License

The MIT License (see the LICENSE file for the full text).

Contact

You can contact us at hello@handsontable.com.