vega-lite-api

vl.param(name)

Define or reference a variable parameter.

param Method Overview

param API Reference

# param.bind(bind)

Input element bindings for this parameter.

See: bind documentation.

The behavior of this method depends on the argument type:

# param.expr(value)

An expression for the value of the parameter. This expression may include other parameters, in which case the parameter will automatically update in response to upstream parameter changes.

# param.name(value)

A unique name for the variable parameter. Parameter names should be valid JavaScript identifiers: they should contain only alphanumeric characters (or “$”, or “_”) and may not start with a digit. Reserved keywords that may not be used as parameter names are “datum”, “event”, “item”, and “parent”.

# param.value(value)

The initial value of the parameter.

Default value: undefined