HyperFormula (v3.0.1)

# Named expressions

An expression can be assigned a human-friendly name. Thanks to this you can refer to that name anywhere across the workbook. Names are especially useful when you use some references repeatedly. In this case, names simplify the formulas and reduce the risk of making a mistake. Such a worksheet is also easier to maintain.

You can name a formula, string, number, or any other type of data.

By default, references in named expressions are absolute. Most people use absolute references in spreadsheet software like Excel without even knowing about it. Very few know that references can be relative too. Unfortunately, HyperFormula doesn't support relative references inside named expressions at the moment.

Dynamic ranges are supported through functions such as INDEX and OFFSET.

Named ranges can overlap each other, e.g., it is possible to define the names as follows:

  • rangeOne: Sheet1!$A$1:$D$10
  • rangeTwo: Sheet1!$A$1:$E$1

# Examples

Type Custom name Example expression
Named cell myCell =Sheet1!$A$1
Named range of cells myRange =Sheet1!$A$1:$D$10
Named constant (number) myNumber =10
Named constant (string) myText ="One Small Step for Man"
Named formula myFormula =SUM(Sheet1!$A$1:$D$10)

# Naming rules

Expression names are case-insensitive, and they:

  • Must start with a Unicode letter or with an underscore (_).
  • Can contain only Unicode letters, numbers, underscores, and periods (.).
  • Can't be the same as any possible reference in the A1 notation (for example, Q4 or YEAR2023).
  • Can't be the same as any possible reference in the R1C1 notation (for example, R4C5, RC or R0C).
  • Must be unique within a given scope.

TIP

Expression names must be unique within a given scope, but you can override a global named-expression with a local one. For example:

// `MyRevenue` has to be unique within the global scope
hfInstance.addNamedExpression('MyRevenue', '=SUM(100+10)');

// but you can still use `MyRevenue` within the local scope of Sheet2 (sheetId = 1)
hfInstance.addNamedExpression('MyRevenue', '=Sheet2!$A$1+100', 1);

For examples of valid and invalid expression names, see the following table:

Name Validity
my Revenue Invalid
myRevenue Valid
quarter1 Invalid
quarter_1 Valid
1stQuarter Invalid
_1stQuarter Valid
.NET Invalid
ASP.NET Valid
A1 Invalid
$A$1 Invalid
RC Invalid

# Using named expressions in formulas

Named expressions can be used in any formula by referencing their names. Use them anywhere you would normally use a cell reference, range, or constant value.

// Define named expressions
hfInstance.addNamedExpression('TaxRate', '=0.08');
hfInstance.addNamedExpression('SalesData', '=Sheet1!$A$1:$A$10');

// Use them in formulas
hfInstance.setCellContents({sheet: 0, col: 2, row: 0}, [['=SUM(SalesData)']]);
hfInstance.setCellContents({sheet: 0, col: 2, row: 1}, [['=SUM(SalesData) * TaxRate']]);

# Available methods

These are the basic methods that can be used to add and manipulate named expressions, including the creation and handling of named ranges. The full list of methods is available in the API reference.

# Adding a named expression

You can add a named expression in two ways:

During engine initialization: You can provide named expressions as a parameter when creating a HyperFormula instance using the factory methods buildEmpty, buildFromArray, or buildFromSheets. This is the most efficient way to add multiple named expressions at once.

// Define named expressions during initialization
const namedExpressions = [
  {
    name: 'prettyName',
    expression: '=Sheet1!$A$1+100',
    scope: 0 // optional: local scope for 'Sheet1'
  },
  {
    name: 'globalConstant', 
    expression: '=42'
    // no scope specified = global scope
  }
];

// Create engine with named expressions
const hfInstance = HyperFormula.buildEmpty({}, namedExpressions);
// or
const hfInstance = HyperFormula.buildFromArray(sheetData, {}, namedExpressions);
// or  
const hfInstance = HyperFormula.buildFromSheets(sheetsData, {}, namedExpressions);

After engine creation: You can add a named expression by using the addNamedExpression method. It accepts name for the expression, the expression as a raw cell content, and optionally the scope. If you do not define the scope it will be set to global, meaning the expression name will be valid for the whole workbook. If you want to add many of them, it is advised to do so in a batch. This method returns an array of changed cells.

// add 'prettyName' expression to the local scope of 'Sheet1' (sheetId = 0)
const changes = hfInstance.addNamedExpression(
  'prettyName',
  '=Sheet1!$A$1+100',
  0
);

# Changing a named expression

You can change a named expression by using the changeNamedExpression method. Select the name of an expression to change and pass it as the first parameter, then define the new expression as raw cell content and optionally add the scope. If you do not define the scope it will be set to global, meaning the expression will be valid for the whole workbook. If you want to change many of them, it is advised to do so in a batch. This method returns an array of changed cells.

// change the named expression
const changes = hfInstance.changeNamedExpression(
  'prettyName',
  '=Sheet1!$A$1+200'
);

# Removing a named expression

You can remove a named expression by using the removeNamedExpression method. Select the name of an expression to remove and pass it as the first parameter and optionally define the scope. If you do not define the scope it will be understood as global, meaning, the whole workbook. This method returns an array of changed cells.

// remove 'prettyName' expression from 'Sheet1' (sheetId=0)
const changes = hfInstance.removeNamedExpression('prettyName', 0);

# Listing all named expressions

You can retrieve a whole list of named expressions by using the listNamedExpressions method. It requires no parameters and returns all named expressions as an array of strings.

// get all named-expression names
const listOfExpressions = hfInstance.listNamedExpressions();

# Handling errors

Operations on named expressions throw errors when something goes wrong. These errors can be handled to provide a good user experience in the application. It is also possible to check the availability of operations using isItPossibleTo* methods, which are also described in that section.

# Demo

A B C D

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