pattern()

Convert a compact notation string into a HapticEvent[] array.

Signature

function pattern<S extends string>(
  notation: S & AssertValidPattern<S>,
): HapticEvent[];

Parameters

Parameter	Type	Description
notation	string	A string of pattern characters

Character reference

Char	Name	Haptic	Cursor advance
o	Soft transient	intensity 0.4, sharpness 0.4	+50 ms
O	Strong transient	intensity 1.0, sharpness 0.8	+50 ms
.	Short gap	—	+100 ms
-	Medium gap	—	+300 ms
=	Long gap	—	+1000 ms

Returns

An array of HapticEvent objects with time, type, intensity, and sharpness fields set.

Usage

import HapticFeedback, { pattern } from "react-native-haptic-feedback";

const events = pattern("oO.O");
// [
//   { time: 0,   type: 'transient', intensity: 0.4, sharpness: 0.4 },
//   { time: 50,  type: 'transient', intensity: 1.0, sharpness: 0.8 },
//   { time: 200, type: 'transient', intensity: 1.0, sharpness: 0.8 },
// ]

HapticFeedback.triggerPattern(events);

Compile-time validation

String literals are validated at compile time via the AssertValidPattern<S> type:

pattern("oO.O"); // ✓
pattern("oXO"); // ✗ TypeScript error — 'X' is not a valid PatternChar

Runtime variables (type string) pass the type check and are validated at runtime instead.

Runtime validation

try {
  HapticFeedback.triggerPattern(pattern(userInput));
} catch (e) {
  if (e instanceof TypeError) {
    // "pattern(): invalid character "x" at position 2.
    //  Allowed characters are: o O . - ="
  }
}

PATTERN_CHARS

The set of valid characters is exported for use in your own validation:

import { PATTERN_CHARS } from "react-native-haptic-feedback";

PATTERN_CHARS; // ReadonlySet<PatternChar> → Set { 'o', 'O', '.', '-', '=' }

const valid = [...str].every((ch) => PATTERN_CHARS.has(ch as any));

AssertValidPattern

A utility type that resolves to the input type for valid strings and never for strings containing invalid characters:

import type { AssertValidPattern } from "react-native-haptic-feedback";

type A = AssertValidPattern<"oO.O">; // 'oO.O'   — valid
type B = AssertValidPattern<"oXO">; // never    — invalid
type C = AssertValidPattern<string>; // string   — runtime variable, passes through

See also

• Pattern notation guide
• Patterns presets
• triggerPattern()