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lazy()

lazy<In, Out>(factory): (input) => Out

Lazy proxy - defers function creation until first call. The factory is called once on the first invocation, then the created function is used directly for all subsequent calls.

Type Parameters​

In: In​

The input type

Out: Out​

The output type

Parameters​

factory: () => (input) => Out​

A function that creates the real function on demand

Returns​

A proxy that initializes lazily

Since​

2.4.0

Example​

// Expensive connection is only created when first needed
const query = lazy(() => {
  const conn = createConnection(); // heavy init
  return (sql: string) => conn.execute(sql);
});

// Nothing happens yet...
query("SELECT 1"); // NOW the connection is created, then query runs
query("SELECT 2"); // reuses the same connection