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Function: byBoolean()

byBoolean<T>(fn): Comparator<T>

Defined in: compare/typed/index.ts:209

Creates a comparator for boolean values.

By default, false comes before true (false < true). Use reverse() for true-first sorting.

Type Parameters​

T​

T

Parameters​

fn​

ComparableExtractor<T, boolean>

Function to extract the boolean value

Returns​

Comparator<T>

A comparator for booleans

Example​

interface Task {
  title: string
  completed: boolean
  urgent: boolean
}

const tasks = [
  { title: 'Review PR', completed: true, urgent: false },
  { title: 'Fix bug', completed: false, urgent: true },
  { title: 'Write docs', completed: false, urgent: false },
  { title: 'Deploy', completed: true, urgent: true }
]

// Sort by completed (incomplete first)
tasks.sort(byBoolean(t => t.completed))
// => [Fix bug (false), Write docs (false), Review PR (true), Deploy (true)]

// Sort by urgent (urgent first)
tasks.sort(reverse(byBoolean(t => t.urgent)))
// => [Fix bug (true), Deploy (true), Review PR (false), Write docs (false)]

// Multi-level: urgent first, then incomplete first
tasks.sort(
  compose(
    reverse(byBoolean(t => t.urgent)),
    byBoolean(t => t.completed)
  )
)

See​

reverse - to sort true values first