mathjs/docs/chained_operations.md

Chained operations

Math.js supports chaining operations by wrapping a value into a Selector. A selector can be created with the function math.select(value). All functions available in the math namespace can be executed via the selector. The functions will be executed with the selectors value as first argument, followed by extra arguments provided by the function call itself.

math.select(3)
    .add(4)
    .subtract(2)
    .done(); // 5

math.select( [[1, 2], [3, 4]] )
    .subset(math.index(0, 0), 8)
    .multiply(3)
    .done(); // [[24, 6], [9, 12]]

Selector API

A Selector is constructed as:

math.select()
math.select(value)

The Selector has all functions available in the math namespace, and has a number of special functions:

• done() Finalize the chained operation and return the selectors value.
• valueOf() The same as done(), returns the selectors value.
• toString() Executes math.format(value) onto the selectors value, returning a string representation of the value.