toBoolean

Returns true for any value not found to be a "false" value. Handles numeric zeros, string literals, and all JavaScript falsy values.

Usage

import { toBoolean } from '@accelint/converters/to-boolean';

console.log(toBoolean(1));          // true
console.log(toBoolean(' FaLsE '));  // false
console.log(toBoolean('  true'));   // true
console.log(toBoolean('000.000'));  // false

Reference

function toBoolean(val: unknown): boolean

Parameters

Parameter	Type	Description
`val`	`unknown`	The value to convert to a boolean.

Returns

Returns true if the value is truthy, false otherwise.

False Values

The following are considered "false" values:

Inherently false: '' (empty string), 0, false, undefined, null, NaN
Numeric zero: '0.000' - any number of leading or trailing zeros
String literal: 'false' - any capitalizations or space-padding

Examples

Example: Basic truthy/falsy

import { toBoolean } from '@accelint/converters/to-boolean';

// Inherently falsy values
console.log(toBoolean(false));      // false
console.log(toBoolean(0));          // false
console.log(toBoolean(''));         // false
console.log(toBoolean(null));       // false
console.log(toBoolean(undefined));  // false
console.log(toBoolean(NaN));        // false

// Truthy values
console.log(toBoolean(true));       // true
console.log(toBoolean(1));          // true
console.log(toBoolean('hello'));    // true
console.log(toBoolean([]));         // true
console.log(toBoolean({}));         // true

Example: Numeric zero detection

import { toBoolean } from '@accelint/converters/to-boolean';

// Various representations of zero
console.log(toBoolean('0'));        // false
console.log(toBoolean('0.0'));      // false
console.log(toBoolean('0.000'));    // false
console.log(toBoolean('000'));      // false
console.log(toBoolean('00.00'));    // false

// Non-zero numbers
console.log(toBoolean('1'));        // true
console.log(toBoolean('0.1'));      // true
console.log(toBoolean('-1'));       // true

Example: String literal 'false'

import { toBoolean } from '@accelint/converters/to-boolean';

// Various forms of the string 'false'
console.log(toBoolean('false'));    // false
console.log(toBoolean('False'));    // false
console.log(toBoolean('FALSE'));    // false
console.log(toBoolean(' false '));  // false
console.log(toBoolean('  FaLsE ')); // false

// Other strings are truthy
console.log(toBoolean('true'));     // true
console.log(toBoolean('True'));     // true
console.log(toBoolean('yes'));      // true
console.log(toBoolean('no'));       // true (not special-cased)

Example: Environment variables

import { toBoolean } from '@accelint/converters/to-boolean';

// Parse environment variable flags
const enableFeature = toBoolean(process.env.ENABLE_FEATURE);
const debugMode = toBoolean(process.env.DEBUG);

// Works with various formats:
// ENABLE_FEATURE=true
// ENABLE_FEATURE=1
// ENABLE_FEATURE=yes
// DEBUG=false
// DEBUG=0

Example: Form input validation

import { toBoolean } from '@accelint/converters/to-boolean';

function validateCheckbox(input: string | undefined): boolean {
  // Handles: "true", "1", "on", or any truthy value
  // Rejects: "false", "0", "", undefined, null
  return toBoolean(input);
}

console.log(validateCheckbox('on'));       // true
console.log(validateCheckbox('true'));     // true
console.log(validateCheckbox('1'));        // true
console.log(validateCheckbox('false'));    // false
console.log(validateCheckbox('0'));        // false
console.log(validateCheckbox(undefined));  // false

Good to know: This function is lenient by design. For more restrictive boolean parsing (e.g., only accepting true/false/on/off/yes/no), see the predicates package (@accelint/predicates).

booleanToNumber - Convert boolean to 1 or 0

toBoolean

On this page