# Cell type

# Overview

The cell type functionality enables you to customize the appearance and validate the cell(s) when applied.

# Usage

There are three functions associated with every table cell: renderer, editor, and optionally validator. These functions are mostly used all together as they are strongly connected.

Example scenario - To store a date in a cell, you would:

  • Use a renderer to display the date using appropriate formatting dd/mm/yyyy, yyyy-mm-dd, etc.
  • Use an editor that displays a calendar instead of the default text input, allowing the user to easily pick the right date.
  • Use a validator to check if the value entered by a user is valid.

Cell type is represented by a string i.e. "text", "numeric", "date". Each string is internally mapped to functions associated with this type e.g., "numeric" type is associated with the following functions:

  • Handsontable.renderers.NumericRenderer
  • Handsontable.editors.TextEditor
  • Handsontable.validators.NumericValidator

When Handsontable encounters a cell with the type option defined, it checks which cell functions this type refers to and uses them. For example, when setting the column type to 'password':

columns: [{
  type: 'password'
}]

the functions editor, renderer, and copyable are automatically set as follows:

columns: [{
  editor: Handsontable.editors.PasswordEditor
  renderer: Handsontable.renderers.PasswordRenderer,
  copyable: false,
}]

# Available cell types

Handsontable comes with nine types:

  • "autocomplete" or Handsontable.cellTypes.autocomplete
  • "checkbox" or Handsontable.cellTypes.checkbox
  • "date" or Handsontable.cellTypes.date
  • "dropdown" or Handsontable.cellTypes.dropdown
  • "handsontable" or Handsontable.cellTypes.handsontable
  • "numeric" or Handsontable.cellTypes.numeric
  • "password" or Handsontable.cellTypes.password
  • "select" or Handsontable.cellTypes.select
  • "time" or Handsontable.cellTypes.time
  • "text" or Handsontable.cellTypes.text

The text cell type is the default type.

# Anatomy of a cell type

A cell type is a predefined set of cell properties. Cell type defines which renderer, editor or validator should be used for a cell. They can also define any different cell property that will be assumed for each matching cell:

Handsontable.cellTypes.registerCellType('custom', {
  renderer: Handsontable.renderers.TextRenderer,
  className: 'my-cell',
  readOnly: true,
  myCustomProperty: 'foo'
})

When used in Handsontable settings:

columns: [{
  type: 'custom'
}]

Is an equivalent to defining them all:

columns: [{
  editor: false,
  renderer: Handsontable.renderers.TextRenderer,
  className: 'my-cell',
  readOnly: true,
  myCustomProperty: 'foo'
}]

# Registering custom cell type

When you create a custom cell type, best practice is to assign it as an alias that will refer to this particular type definition.

This gives users a convenient way of defining which cell type should be used for describing cell properties. The user doesn't need to know which part of the code is responsible for rendering, validating, or editing the cell value. They do not even need to know that there are any functions at all. You can change the cell behaviour associated with an alias without changing the code that defines a cell's properties.

To register your own alias use Handsontable.cellTypes.registerCellType() function. It takes two arguments:

  • cellTypeName - a string representing the cell type object
  • type - an object with keys editor, renderer, and validator that will be represented by cellTypeName

If you'd like to register copyablePasswordType under alias copyable-password, you need to call:

Handsontable.cellTypes.registerCellType('copyable-password', {
  editor: copyablePasswordEditor,
  renderer: copyablePasswordRenderer,
});

Choose aliases wisely. If you register your cell type under name that is already registered, the target function will be overwritten:

Handsontable.cellTypes.registerCellType('password', {
  editor: copyablePasswordEditor,
  renderer: copyablePasswordRenderer,
});

// Now 'password' alias points to the newly created
// object, not Handsontable.cellTypes.password

Unless you intentionally want to overwrite an existing alias, try to choose a unique name. Best practice is to prefix your aliases with a custom name to minimize the possibility of name collisions. This is especially important if you want to publish your cell type as you never know what aliases have been registered by a user who uses your cell type.

Handsontable.cellTypes.registerCellType('copyable-password', {
  editor: copyablePasswordEditor,
  renderer: copyablePasswordRenderer,
});

Someone might already registered such alias. It would be better use a unique prefix:

Handsontable.cellTypes.registerCellType('my.copyable-password', {
  editor: copyablePasswordEditor,
  renderer: copyablePasswordRenderer,
});

To sum up, a well-prepared cell type object should look like this:

var MyEditor = Handsontable.editors.TextEditor.prototype.extend();

function customRenderer(instance, td, row, column, prop, value, cellProperties) {
  // ...renderer logic
}

function customValidator(query, callback) {
  // ...validator logic
  callback(/* Pass `true` or `false` */);
}

// Register an alias
Handsontable.cellTypes.registerCellType('my.custom', {
  editor: MyEditor,
  renderer: customRenderer,
  validator: customValidator,
  // You can add additional options to the cell type
  // based on Handsontable settings
  className: 'my-cell',
  allowInvalid: true,
  // Or you can add custom properties which
  // will be accessible in `cellProperties`
  myCustomCellState: 'complete',
});

# Using an alias

The next step is to use the registered aliases to enable users to easily refer to them without the need to know what the actual cell type object is. Here's an example of how you would use your cell definition:

const hot = new Handsontable(container, {
  columns: [{
    type: 'my.custom'
  }]
});

# Precedence

It is possible to define the type option together with options such as renderer, editor or validator. For example:

const hot = new Handsontable(container, {
  columns: [{
    type: 'numeric',
    // validator function defined elsewhere
    validator: customValidator
  }]
});

We defined the type for all cells in a column to be numeric. We also defined a validator function directly. In Handsontable, cell functions that are defined directly always take precedence over functions associated with cell type, so the above configuration is equivalent to:

const hot = new Handsontable(container, {
  columns: [{
    renderer: Handsontable.renderers.NumericRenderer,
    editor: Handsontable.editors.TextEditor,
    validator: customValidator
  }]
});

There is one more way you can define the configuration using types:

const hot = new Handsontable(container, {
  // validator function defined elsewhere
  validator: customValidator,
  columns: [
    { type: 'password' },
    { }
  columns: [{
    type: 'my.custom'
  }]
});

Using cascade configuration we define a table with two columns, with validator set to customValidator function. The type of the first column is set to password. The Password cell type does not define a validator function:

{
  renderer: Handsontable.renderers.PasswordRenderer,
  editor: Handsontable.editors.PasswordEditor,
  validator: undefined
}

Because type: 'password' is a more specific configuration for the cells in the first column than the validator: customValidator, cell functions associated with the password type take precedence over the functions defined on the higher level of configuration. Therefore, the equivalent configuration is:

const hot = new Handsontable(container, {
  columns: [{
    renderer: Handsontable.renderers.PasswordRenderer,
    editor: Handsontable.editors.PasswordEditor,
    validator: undefined
  }, {
    renderer: Handsontable.renderers.TextRenderer,
    editor: Handsontable.editors.TextEditor,
    validator: customValidator
  }]
});

# Built-in cell types example

The example below shows some of the built-in cell types, i.e. combinations of cell renderers and editors available in Handsontable. The example also shows the declaration of custom cell renderers, namely yellowRenderer and greenRenderer.

    # Empty cells

    It's worth to mention that values such as '' (empty string), null and undefined are considered empty values. You can use the Handsontable.helper.isEmpty method to check whether a value is considered empty. Cells with empty values are displayed in a similar way for most of the data types (see below).

    TIP

    Please keep in mind that opening a cell with undefined and null values results in overwriting the original value with an empty string. Moreover, copying and pasting that values will result in pasting the empty string.

      Empty cells may be treated in differently in different contexts, for example, the ColumnSorting plugin has sortEmptyCells option which is responsible for establishing whether empty cells should be sorted like non-empty cells.