ts-predicate

Getting started

``bash
yarn add ts-predicate


or


npm install ts-predicate
`

Documentation

- TypeAssertion
- TypeGuard
- TypeHint
- ValueGuard

TypeAssertion

$3

`ts
static IsDefined(value: unknown): void
`

Asserts that the value is not nullable, nor NaN.

$3

`ts
static IsBoolean(value: unknown): void
`

Asserts that the value is a boolean.

$3

`ts
static IsNumber(value: unknown): void
`

Asserts that the value is a number, but not NaN.

$3

`ts
static IsInteger(value: unknown): void
`

Asserts that the value is a safe integer.

$3

`ts
static IsFiniteNumber(value: unknown): void
`

Asserts that the value is a number, but not NaN nor +/-Infinity.

$3

`ts
static IsString(value: unknown, constraints?: StringConstraints): void
`

Asserts that the value is a string.

The optional parameter constraints accept an object described by the following interface.

`ts
interface StringConstraints
{
minLength?: number;
maxLength?: number;
}
`

If minLength is provided, it'll asserts that the value has at least this length.

If maxLength is provided, it'll asserts that the value has at most this length.

$3

`ts
static IsFilledString(value: unknown): void
`

Like IsString, but asserts that the string is never empty too.

$3

`ts
static IsArray(value: unknown, constraints?: ArrayConstraints): void
`

Asserts that the value is an array.

The optional parameter constraints accept an object described by the following interface.

`ts
interface ArrayConstraints
{
minLength?: number;
itemGuard?: (item: unknown) => item is T;
}
`

If minLength is provided, it'll asserts that the value has at least that many items.

If itemGuard is provided, it'll asserts that the predicate hold true for every item.

$3

`ts
static IsPopulatedArray(value: unknown, constraints?: ArrayConstraints): void
`

Like IsArray, but asserts that the array is never empty too.

$3

`ts
static IsRecord(value: unknown): void
`

Asserts that the value is a record: an object with no prototype, or directly
using Object prototype.

$3

`ts
static IsObject(value: unknown): void
`

Asserts that the value is an object.

$3

`ts
static IsFunction(value: unknown): void
`

Asserts that the value is a function, generator function, method, or class.

$3

`ts
static IsCallable(value: unknown): void
`

Asserts that the value is not constructible.

$3

`ts
static HasNullableProperty(value: object, property: string): void
`

Asserts that the value is an object with the property defined, though it may be nullish or NaN.

$3

`ts
static HasProperty(value: object, property: string): void
`

Asserts that the value is an object with the property defined.

TypeGuard

$3

`ts
static IsPrimitive(value: unknown): boolean
`

Narrow down the value to being nullish, NaN, a boolean, a number, or a string.

$3

`ts
static IsDefined(value: unknown): boolean
`

Narrow down the value to being not nullable, nor NaN.

$3

`ts
static IsBoolean(value: unknown): boolean
`

Narrow down the value to being a boolean.

$3

`ts
static IsNumber(value: unknown): boolean
`

Narrow down the value to being a number, but not NaN.

$3

`ts
static IsInteger(value: unknown): boolean
`

Narrow down the value to being a safe integer.

$3

`ts
static IsFiniteNumber(value: unknown): boolean
`

Narrow down the value to being a number, but not NaN nor +/-Infinity.

$3

`ts
static IsString(value: unknown): boolean
`

Narrow down the value to being a string.

$3

`ts
static IsFilledString(value: unknown): void
`

Asserts that the value is a non empty string.

$3

`ts
static IsArray(value: unknown, constraints?: ArrayConstraints): boolean
`

Narrow down the value to being an array.

The optional parameter constraints accept an object described by the following interface.

`ts
interface ArrayConstraints
{
minLength?: number;
itemGuard?: (item: unknown) => item is T;
}
`

If minLength is provided, it'll confirm that the value has at least that many items.

If itemGuard is provided, it'll confirm that the predicate hold true for every item.

$3

`ts
static IsPopulatedArray(value: unknown, constraints?: ArrayConstraints): boolean
`

Like IsArray, but narrow it to being a populated array.

$3

`ts
static IsRecord(value: unknown): boolean
`

Narrow down the value to being a record: an object with no prototype, or directly using Object prototype.

$3

`ts
static IsObject(value: unknown): boolean
`

Narrow down the value to being an object.

$3

`ts
static IsFunction(value: unknown): boolean
`

Narrow down the value to being a function, generator function, method, or class.

$3

`ts
static IsCallable(value: unknown): boolean
`

Narrow down the value to being not constructible.

$3

`ts
static HasNullableProperty(value: object, property: string): boolean
`

Narrow down the value to being an object with the property defined, though it may be nullish or NaN.

$3

`ts
static HasProperty(value: object, property: string): boolean
`

Narrow down the value to being an object with the property defined.

TypeHint

$3

`ts
static GetBaseType(value: any): string
`

Return a string depending on the type of the given value.

Possible values:

- undefined
- null
- NaN
- boolean
- number
- string
- array
- object
- function
- generator
- class

Note: generator refers to a generator function.

$3

`ts
static GetDetailedType(value: any): string
`

Return a string depending on the type of the given value.

Provide more details than GetBaseType.

Possible values:

- undefined
- null
- NaN
- boolean (true or false)
- number (N)
- string (N characters)
- array (N items)
- anonymous object
- object anonymous class
- object ClassName
- anonymous function
- function name
- anonymous generator
- generator name
- anonymous class
- class Name

Note: generator refers to a generator function.

$3

`ts
static GetName(value: any): string|undefined
`

If given a function, generator function, method, or class, return its name.

If given an object, return its constructor name.

If the given value doesn't have a name, return an empty string.

For any other value, return undefined.

ValueGuard

$3

`ts
static IsSimilar(a: any, b: any): boolean
``

Return true in the following cases :

- The same value has been passed as both arguments.
- Similar primitive values have been passed as arguments.
- Deeply similar arrays or records have been passed as arguments.

Otherwise, return false.