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anyNumber

Accepts any valid number value. This also accepts special values like NaN and Infinity. Unless you want to deliberately accept those, you’ll likely want to use the number decoder instead. 
const anyNumber: Decoder<number>

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Example

import { anyNumber } from 'decoders';

anyNumber.decode(42);         // ✓ 42
anyNumber.decode(3.14);       // ✓ 3.14
anyNumber.decode(NaN);        // ✓ NaN
anyNumber.decode(Infinity);   // ✓ Infinity
anyNumber.decode('42');       // ✗ Error: Must be number

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number

Accepts finite numbers (can be integer or float values). Values NaN, or positive and negative Infinity will get rejected. 
const number: Decoder<number>

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Example

import { number } from 'decoders';

number.decode(42);         // ✓ 42
number.decode(3.14);       // ✓ 3.14
number.decode(NaN);        // ✗ Error: Number must be finite
number.decode(Infinity);   // ✗ Error: Number must be finite

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integer

Accepts only finite whole numbers. 
const integer: Decoder<number>

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Example

import { integer } from 'decoders';

integer.decode(42);    // ✓ 42
integer.decode(-10);   // ✓ -10
integer.decode(3.14);  // ✗ Error: Number must be an integer

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positiveNumber

Accepts only non-negative (zero or positive) finite numbers. 
const positiveNumber: Decoder<number>

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Example

import { positiveNumber } from 'decoders';

positiveNumber.decode(42);     // ✓ 42
positiveNumber.decode(0);      // ✓ 0
positiveNumber.decode(3.14);   // ✓ 3.14
positiveNumber.decode(-5);     // ✗ Error: Number must be positive

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positiveInteger

Accepts only non-negative (zero or positive) finite whole numbers. 
const positiveInteger: Decoder<number>

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Example

import { positiveInteger } from 'decoders';

positiveInteger.decode(42);    // ✓ 42
positiveInteger.decode(0);     // ✓ 0
positiveInteger.decode(-5);    // ✗ Error: Number must be positive
positiveInteger.decode(3.14);  // ✗ Error: Number must be an integer

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min

Accepts numbers greater than or equal to the given minimum. Defaults to the number decoder if none is provided. Pass a different decoder to further restrict accepted values, e.g. min(0, integer). 
function min(min: number, decoder?: Decoder<number>): Decoder<number>

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Parameters

  • min - The minimum allowed value (inclusive)
  • decoder - Optional base decoder (defaults to number)

​
Example

import { min, integer } from 'decoders';

const atLeast10 = min(10);
atLeast10.decode(15);    // ✓ 15
atLeast10.decode(10);    // ✓ 10
atLeast10.decode(5);     // ✗ Error: Too low, must be at least 10

// With integer constraint
const atLeast10Int = min(10, integer);
atLeast10Int.decode(15);    // ✓ 15
atLeast10Int.decode(15.5);  // ✗ Error: Number must be an integer

​
max

Accepts numbers less than or equal to the given maximum. Defaults to the number decoder if none is provided. Pass a different decoder to further restrict accepted values, e.g. max(100, integer). 
function max(max: number, decoder?: Decoder<number>): Decoder<number>

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Parameters

  • max - The maximum allowed value (inclusive)
  • decoder - Optional base decoder (defaults to number)

​
Example

import { max, integer } from 'decoders';

const atMost100 = max(100);
atMost100.decode(50);    // ✓ 50
atMost100.decode(100);   // ✓ 100
atMost100.decode(150);   // ✗ Error: Too high, must be at most 100

// With integer constraint
const atMost100Int = max(100, integer);
atMost100Int.decode(50);    // ✓ 50
atMost100Int.decode(50.5);  // ✗ Error: Number must be an integer

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between

Accepts numbers within the given range (bounds are inclusive). Defaults to the number decoder if none is provided. Pass a different decoder to further restrict accepted values, e.g. between(1, 10, integer). 
function between(
  min: number,
  max: number,
  decoder?: Decoder<number>
): Decoder<number>

​
Parameters

  • min - The minimum allowed value (inclusive)
  • max - The maximum allowed value (inclusive)
  • decoder - Optional base decoder (defaults to number)

​
Example

import { between, integer } from 'decoders';

const percentage = between(0, 100);
percentage.decode(50);     // ✓ 50
percentage.decode(0);      // ✓ 0
percentage.decode(100);    // ✓ 100
percentage.decode(150);    // ✗ Error: Too high, must be between 0 and 100
percentage.decode(-10);    // ✗ Error: Too low, must be between 0 and 100

// Dice roll (1-6, integers only)
const diceRoll = between(1, 6, integer);
diceRoll.decode(4);      // ✓ 4
diceRoll.decode(3.5);    // ✗ Error: Number must be an integer

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