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JavaScript Data Grid: Column Definitions

Each column in the grid is defined using a Column Definition (ColDef). Columns are positioned in the grid according to the order the Column Definitions are specified in the Grid Options.

The following example shows a simple grid with 3 columns defined:

const gridOptions = {
    // define 3 columns
    columnDefs: [
        { headerName: 'Athlete', field: 'athlete' },
        { headerName: 'Sport', field: 'sport' },
        { headerName: 'Age', field: 'age' },

    // other grid options ...

See Column Properties for a list of all properties that can be applied to a column.

If you want the columns to be grouped, you can include them as children like so:

// put the three columns into a group
columnDefs: [
        headerName: 'Group A',
        children: [
            { headerName: 'Athlete', field: 'athlete' },
            { headerName: 'Sport', field: 'sport' },
            { headerName: 'Age', field: 'age' },

Groups are explained in more detail in the section Column Groups.

Custom Column Types

In addition to the above, the grid provides additional ways to help simplify and avoid duplication of column definitions. This is done through the following:

  • defaultColDef: contains properties that all columns will inherit.
  • defaultColGroupDef: contains properties that all column groups will inherit.
  • columnTypes: specific column types containing properties that column definitions can inherit.

Default columns and column types can specify any of the column properties available on a column.

Column Types are designed to work on Columns only, i.e. they won't be applied to Column Groups.

The following code snippet demonstrates these three properties:

const gridOptions = {
    columnDefs: [
        // uses the default column properties
        { headerName: 'Col A', field: 'a'},
        // overrides the default with a number filter
        { headerName: 'Col B', field: 'b', filter: 'agNumberColumnFilter' },
        // overrides the default using a column type
        { headerName: 'Col C', field: 'c', type: 'nonEditableColumn' },
        // overrides the default using a multiple column types
        { headerName: 'Col D', field: 'd', type: ['dateColumn', 'nonEditableColumn'] }

    // a default column definition with properties that get applied to every column
    defaultColDef: {
        // set every column width
        width: 100,
        // make every column editable
        editable: true,
        // make every column use 'text' filter by default
        filter: 'agTextColumnFilter',

    // if we had column groups, we could provide default group items here
    defaultColGroupDef: {},

    // define a column type (you can define as many as you like)
    columnTypes: {
        nonEditableColumn: { editable: false },
        dateColumn: {
            filter: 'agDateColumnFilter',
            filterParams: { comparator: myDateComparator },
            suppressMenu: true

    // other grid options ...

When the grid creates a column it starts with the default column definition, then adds in anything from the column type, then finally adds in items from the specific column definition.

For example, the following is an outline of the steps used when creating 'Col C' shown above:

// Step 1: the grid starts with an empty definition

// Step 2: default column properties are merged in
{ width: 100, editable: true, filter: 'agTextColumnFilter' }

// Step 3: column type properties are merged in (using the 'type' property)
{ width: 100, editable: false, filter: 'agTextColumnFilter' }

// Step 4: finally column definition properties are merged in
{ headerName: 'Col C', field: 'c', width: 100, editable: false, filter: 'agTextColumnFilter' }

The following example demonstrates the different configuration properties in action.

Right Aligned and Numeric Columns

The grid provides a handy shortcut for aligning columns to the right. Setting the column definition type to rightAligned aligns the column header and contents to the right, which makes the scanning of the data easier for the user.

Because right alignment is used for numbers, we also provided an alias numericColumn that can be used to align the header and cell text to the right.

const gridOptions = {
    columnDefs: [
        { headerName: 'Column A', field: 'a' },
        { headerName: 'Column B', field: 'b', type: 'rightAligned' },
        { headerName: 'Column C', field: 'c', type: 'numericColumn' },

    // other grid options ...

Column IDs

Each column generated by the grid is given a unique Column ID, which is used in parts of the Grid API.

If you are using the API and the columns IDs are a little complex (e.g. if two columns have the same field, or if you are using valueGetter instead of field) then it is useful to understand how columns IDs are generated.

If the user provides colId in the column definition, then this is used, otherwise the field is used. If both colId and field exist then colId gets preference. If neither colId nor field exists then a number is assigned. Finally, the ID is ensured to be unique by appending '_n' if necessary, where n is the first positive number that allows uniqueness.

In the example below, columns are set up to demonstrate the different ways IDs are generated. Open the example in a new tab and observe the output in the dev console. Note the following:

  • Col 1 and Col 2 both use colId. The grid appends '_1' to Col 2 to make the ID unique.
  • Col 3 and Col 4 both use field. The grid appends '_1' to Col 4 to make the ID unique.
  • Col 5 and Col 6 have neither colId or field so the grid generates column IDs.