Product
Announcing Precomputed Reachability Analysis in Socket
Socket’s precomputed reachability slashes false positives by flagging up to 80% of vulnerabilities as irrelevant, with no setup and instant results.
By Martin Torp - Jul 30, 2025
You're Invited:Meet the Socket Team at BlackHat and DEF CON in Las Vegas, Aug 4-6.RSVP →
@xylabs/typeof
Advanced tools
@xylabs/typeof
Base functionality used throughout XY Labs TypeScript/JavaScript libraries
@xylabs/typeof
Base functionality used throughout XY Labs TypeScript/JavaScript libraries
Reference
@xylabs/typeof
Type Aliases
- FieldType
- ObjectTypeShape
- TypeOfTypes
- TypedValue
- TypedKey
- TypedObject
- TypedArray
- AnyFunction
- RecordKey
Functions
- isTypedKey
- isTypedValue
- isTypedArray
- isValidTypedFieldPair
- isTypedObject
- ifDefined
- ifTypeOf
- isUndefined
- isDefined
- isNull
- isDefinedNotNull
- isUndefinedOrNull
- isBigInt
- isString
- isNumber
- isObject
- isArray
- isFunction
- isSymbol
- isEmptyObject
- isEmptyString
- isEmptyArray
- isPopulatedArray
- isEmpty
- isFalsy
- isTruthy
- isBoolean
- isDateString
- isDate
- isRegExp
- isError
- isPromise
- isPromiseLike
- isMap
- isArrayBufferView
- isSet
- isWeakMap
- isWeakSet
- isArrayBuffer
- isDataView
- isBlob
- isFile
- isType
- typeOf
- validateType
functions
ifDefined
function ifDefined<T>(value, func): undefined | T;
Type Parameters
T
T
Parameters
value
T
func
(value) => void
Returns
undefined | T
ifTypeOf
function ifTypeOf<T, R>(
typeName,
value,
trueFunc,
isFunc?): undefined | R;
Type Parameters
T
T
R
R
Parameters
typeName
value
unknown
trueFunc
(value) => R
isFunc?
(value) => boolean
Returns
undefined | R
isArray
Call Signature
function isArray(value): value is [];
Parameters
value
unknown
Returns
value is []
Call Signature
function isArray<T>(value): value is Extract<T, unknown[]>;
Type Parameters
T
T extends []
Parameters
value
T
Returns
value is Extract<T, unknown[]>
isArrayBuffer
Call Signature
function isArrayBuffer(value): value is ArrayBuffer;
Parameters
value
unknown
Returns
value is ArrayBuffer
Call Signature
function isArrayBuffer<T>(value): value is Extract<T, ArrayBuffer>;
Type Parameters
T
T extends ArrayBuffer
Parameters
value
T
Returns
value is Extract<T, ArrayBuffer>
isArrayBufferView
Call Signature
function isArrayBufferView(value): value is ArrayBufferView<ArrayBufferLike>;
Parameters
value
unknown
Returns
value is ArrayBufferView<ArrayBufferLike>
Call Signature
function isArrayBufferView<T>(value): value is Extract<T, ArrayBufferView<ArrayBufferLike>>;
Type Parameters
T
T extends ArrayBufferView<ArrayBufferLike>
Parameters
value
T
Returns
value is Extract<T, ArrayBufferView<ArrayBufferLike>>
isBigInt
Call Signature
function isBigInt(value): value is bigint;
Parameters
value
unknown
Returns
value is bigint
Call Signature
function isBigInt<T>(value): value is Extract<T, bigint>;
Type Parameters
T
T extends bigint
Parameters
value
T
Returns
value is Extract<T, bigint>
isBlob
Call Signature
function isBlob(value): value is Blob;
Parameters
value
unknown
Returns
value is Blob
Call Signature
function isBlob<T>(value): value is Extract<T, Blob>;
Type Parameters
T
T extends Blob
Parameters
value
T
Returns
value is Extract<T, Blob>
isBoolean
Call Signature
function isBoolean(value): value is boolean;
Parameters
value
unknown
Returns
value is boolean
Call Signature
function isBoolean<T>(value): value is Extract<T, boolean>;
Type Parameters
T
T extends boolean
Parameters
value
T
Returns
value is Extract<T, boolean>
isDataView
Call Signature
function isDataView(value): value is DataView<ArrayBufferLike>;
Parameters
value
unknown
Returns
value is DataView<ArrayBufferLike>
Call Signature
function isDataView<T>(value): value is Extract<T, DataView<ArrayBufferLike>>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, DataView<ArrayBufferLike>>
isDate
Call Signature
function isDate(value): value is Date;
Parameters
value
unknown
Returns
value is Date
Call Signature
function isDate<T>(value): value is Extract<T, Date>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, Date>
isDateString
Call Signature
function isDateString(value): value is string;
Parameters
value
unknown
Returns
value is string
Call Signature
function isDateString<T>(value): value is Extract<T, string>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, string>
isDefined
function isDefined<T>(value): value is Exclude<T, undefined>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Exclude<T, undefined>
isDefinedNotNull
function isDefinedNotNull<T>(value): value is Exclude<T, undefined | null>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Exclude<T, undefined | null>
isEmpty
Call Signature
function isEmpty<T>(value): value is T;
Type Parameters
T
T
Parameters
value
unknown
Returns
value is T
Call Signature
function isEmpty<K, V, T>(value): value is Extract<T, Record<K, never>>;
Type Parameters
K
K extends RecordKey
V
V
T
T extends Record<K, V>
Parameters
value
T
Returns
value is Extract<T, Record<K, never>>
Call Signature
function isEmpty<T>(value): value is Extract<T, never[]>;
Type Parameters
T
T extends unknown[]
Parameters
value
T
Returns
value is Extract<T, never[]>
isEmptyArray
Call Signature
function isEmptyArray(value): value is [];
Parameters
value
unknown
Returns
value is []
Call Signature
function isEmptyArray<T>(value): value is Extract<T, unknown[]>;
Type Parameters
T
T extends unknown[]
Parameters
value
T
Returns
value is Extract<T, unknown[]>
isEmptyObject
Call Signature
function isEmptyObject(value): value is {};
Parameters
value
unknown
Returns
value is {}
Call Signature
function isEmptyObject<K, V, T>(value): value is Extract<T, Record<K, never>>;
Type Parameters
K
K extends RecordKey
V
V
T
T extends Record<K, V>
Parameters
value
T
Returns
value is Extract<T, Record<K, never>>
isEmptyString
Call Signature
function isEmptyString(value): value is "";
Parameters
value
unknown
Returns
value is ""
Call Signature
function isEmptyString<T>(value): value is Extract<T, "">;
Type Parameters
T
T extends string
Parameters
value
T
Returns
value is Extract<T, "">
isError
Call Signature
function isError(value): value is Error;
Parameters
value
unknown
Returns
value is Error
Call Signature
function isError<T>(value): value is Extract<T, Error>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, Error>
isFalsy
Call Signature
function isFalsy<T>(value): value is Extract<T, undefined | null | false | "" | 0 | 0n>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, undefined | null | false | "" | 0 | 0n>
Call Signature
function isFalsy<T>(value): value is Extract<T, false>;
Type Parameters
T
T extends boolean
Parameters
value
T
Returns
value is Extract<T, false>
Call Signature
function isFalsy<T>(value): value is Extract<T, 0>;
Type Parameters
T
T extends number
Parameters
value
T
Returns
value is Extract<T, 0>
Call Signature
function isFalsy<T>(value): value is Extract<T, 0n>;
Type Parameters
T
T extends bigint
Parameters
value
T
Returns
value is Extract<T, 0n>
Call Signature
function isFalsy<T>(value): value is Extract<T, null>;
Type Parameters
T
T extends null
Parameters
value
T
Returns
value is Extract<T, null>
Call Signature
function isFalsy<T>(value): value is Extract<T, undefined>;
Type Parameters
T
T extends undefined
Parameters
value
T
Returns
value is Extract<T, undefined>
Call Signature
function isFalsy<T>(value): value is Extract<T, "">;
Type Parameters
T
T extends string
Parameters
value
T
Returns
value is Extract<T, "">
isFile
Call Signature
function isFile(value): value is File;
Parameters
value
unknown
Returns
value is File
Call Signature
function isFile<T>(value): value is Extract<T, File>;
Type Parameters
T
T extends File
Parameters
value
T
Returns
value is Extract<T, File>
isFunction
Call Signature
function isFunction(value): value is AnyFunction;
Parameters
value
unknown
Returns
value is AnyFunction
Call Signature
function isFunction<T>(value): value is Extract<T, AnyFunction>;
Type Parameters
T
T extends AnyFunction
Parameters
value
T
Returns
value is Extract<T, AnyFunction>
isMap
Call Signature
function isMap(value): value is Map<unknown, unknown>;
Parameters
value
unknown
Returns
value is Map<unknown, unknown>
Call Signature
function isMap<K, V, T>(value): value is Extract<T, Map<K, V>>;
Type Parameters
K
K
V
V
T
T extends Map<K, V>
Parameters
value
T
Returns
value is Extract<T, Map<K, V>>
isNull
Call Signature
function isNull(value): value is null;
Parameters
value
unknown
Returns
value is null
Call Signature
function isNull<T>(value): value is Extract<T, null>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, null>
isNumber
Call Signature
function isNumber(value): value is number;
Parameters
value
unknown
Returns
value is number
Call Signature
function isNumber<T>(value): value is Extract<T, number>;
Type Parameters
T
T extends number
Parameters
value
T
Returns
value is Extract<T, number>
isObject
Call Signature
function isObject(value): value is object;
Parameters
value
unknown
Returns
value is object
Call Signature
function isObject<T>(value): value is Extract<T, object>;
Type Parameters
T
T extends object
Parameters
value
T
Returns
value is Extract<T, object>
isPopulatedArray
Call Signature
function isPopulatedArray(value): value is [];
Parameters
value
unknown
Returns
value is []
Call Signature
function isPopulatedArray<T>(value): value is Extract<T, unknown[]>;
Type Parameters
T
T extends unknown[]
Parameters
value
T
Returns
value is Extract<T, unknown[]>
isPromise
Call Signature
function isPromise(value): value is Promise<unknown>;
Parameters
value
unknown
Returns
value is Promise<unknown>
Call Signature
function isPromise<T>(value): value is Extract<T, Promise<unknown>>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, Promise<unknown>>
isPromiseLike
Call Signature
function isPromiseLike(value): value is Promise<unknown>;
Parameters
value
unknown
Returns
value is Promise<unknown>
Call Signature
function isPromiseLike<T>(value): value is Extract<T, Promise<unknown>>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, Promise<unknown>>
isRegExp
Call Signature
function isRegExp(value): value is RegExp;
Parameters
value
unknown
Returns
value is RegExp
Call Signature
function isRegExp<T>(value): value is Extract<T, RegExp>;
Type Parameters
T
T extends RegExp
Parameters
value
T
Returns
value is Extract<T, RegExp>
isSet
Call Signature
function isSet(value): value is Set<unknown>;
Parameters
value
unknown
Returns
value is Set<unknown>
Call Signature
function isSet<T>(value): value is Extract<T, Set<unknown>>;
Type Parameters
T
T extends Set<unknown>
Parameters
value
unknown
Returns
value is Extract<T, Set<unknown>>
isString
Call Signature
function isString(value): value is string;
Parameters
value
unknown
Returns
value is string
Call Signature
function isString<T>(value): value is Extract<T, string>;
Type Parameters
T
T extends string
Parameters
value
T
Returns
value is Extract<T, string>
isSymbol
Call Signature
function isSymbol(value): value is symbol;
Parameters
value
unknown
Returns
value is symbol
Call Signature
function isSymbol<T>(value): value is Extract<T, symbol>;
Type Parameters
T
T extends symbol
Parameters
value
T
Returns
value is Extract<T, symbol>
isTruthy
Call Signature
function isTruthy<T>(value): value is Exclude<T, undefined | null | false | "" | 0 | 0n>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Exclude<T, undefined | null | false | "" | 0 | 0n>
Call Signature
function isTruthy<T>(value): value is Extract<T, true>;
Type Parameters
T
T extends boolean
Parameters
value
T
Returns
value is Extract<T, true>
Call Signature
function isTruthy<T>(value): value is Extract<T, number>;
Type Parameters
T
T extends number
Parameters
value
T
Returns
value is Extract<T, number>
Call Signature
function isTruthy<T>(value): value is Extract<T, bigint>;
Type Parameters
T
T extends bigint
Parameters
value
T
Returns
value is Extract<T, bigint>
Call Signature
function isTruthy<T>(value): value is Extract<T, null>;
Type Parameters
T
T extends null
Parameters
value
T
Returns
value is Extract<T, null>
Call Signature
function isTruthy<T>(value): value is Extract<T, undefined>;
Type Parameters
T
T extends undefined
Parameters
value
T
Returns
value is Extract<T, undefined>
Call Signature
function isTruthy<T>(value): value is Extract<T, string>;
Type Parameters
T
T extends string
Parameters
value
T
Returns
value is Extract<T, string>
isType
function isType(value, expectedType): boolean;
Parameters
value
unknown
expectedType
Returns
boolean
isTypedArray
function isTypedArray(value): value is TypedArray;
Parameters
value
unknown
Returns
value is TypedArray
isTypedKey
function isTypedKey(value): value is string | number | symbol;
Parameters
value
unknown
Returns
value is string | number | symbol
isTypedObject
function isTypedObject(value): value is TypedObject;
Parameters
value
unknown
Returns
value is TypedObject
isTypedValue
function isTypedValue(value): value is TypedValue;
Parameters
value
unknown
Returns
value is TypedValue
isUndefined
Call Signature
function isUndefined(value): value is undefined;
Parameters
value
unknown
Returns
value is undefined
Call Signature
function isUndefined<T>(value): value is Extract<T, undefined>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, undefined>
isUndefinedOrNull
Call Signature
function isUndefinedOrNull(value): value is undefined | null;
Parameters
value
unknown
Returns
value is undefined | null
Call Signature
function isUndefinedOrNull<T>(value): value is Extract<T, undefined | null>;
Type Parameters
T
T
Parameters
value
T
Returns
value is Extract<T, undefined | null>
isValidTypedFieldPair
function isValidTypedFieldPair(pair): pair is [key: string | number | symbol, value: TypedValue];
Parameters
pair
[unknown, unknown]
Returns
pair is [key: string | number | symbol, value: TypedValue]
isWeakMap
Call Signature
function isWeakMap(value): value is WeakMap<WeakKey, unknown>;
Parameters
value
unknown
Returns
value is WeakMap<WeakKey, unknown>
Call Signature
function isWeakMap<K, V, T>(value): value is Extract<T, WeakMap<K, V>>;
Type Parameters
K
K extends WeakKey
V
V
T
T extends WeakMap<K, V>
Parameters
value
T
Returns
value is Extract<T, WeakMap<K, V>>
isWeakSet
Call Signature
function isWeakSet(value): value is WeakSet<WeakKey>;
Parameters
value
unknown
Returns
value is WeakSet<WeakKey>
Call Signature
function isWeakSet<K, T>(value): value is Extract<T, WeakSet<K>>;
Type Parameters
K
K extends WeakKey
T
T extends WeakSet<K>
Parameters
value
T
Returns
value is Extract<T, WeakSet<K>>
typeOf
function typeOf<T>(item): TypeOfTypes;
Type Parameters
T
T
Parameters
item
T
Returns
validateType
function validateType<T>(
typeName,
value,
optional): [undefined | T, Error[]];
Type Parameters
T
T
Parameters
typeName
value
T
optional
boolean = false
Returns
[undefined | T, Error[]]
type-aliases
AnyFunction
type AnyFunction = (...args) => unknown;
Parameters
args
...unknown[]
Returns
unknown
FieldType
type FieldType =
| "string"
| "number"
| "object"
| "symbol"
| "undefined"
| "null"
| "array"
| "function";
ObjectTypeShape
type ObjectTypeShape = Record<string | number | symbol, FieldType>;
RecordKey
type RecordKey = string | number | symbol;
TypeOfTypes
type TypeOfTypes =
| "string"
| "number"
| "object"
| "array"
| "buffer"
| "null"
| "undefined"
| "bigint"
| "boolean"
| "function"
| "symbol";
TypedArray
type TypedArray = TypedValue[];
TypedKey
type TypedKey<T> = T extends string ? T : string | number | symbol;
Type Parameters
T
T extends string | void = void
TypedObject
type TypedObject =
| {
[key: string | number | symbol]: TypedValue;
}
| object;
TypedValue
type TypedValue =
| bigint
| string
| number
| boolean
| null
| TypedObject
| TypedArray
| Function
| symbol
| undefined;
Part of sdk-js
Maintainers
License
See the LICENSE file for license details
Credits
Keywords
FAQs
Base functionality used throughout XY Labs TypeScript/JavaScript libraries
The npm package @xylabs/typeof receives a total of 5,153 weekly downloads. As such, @xylabs/typeof popularity was classified as popular.
We found that @xylabs/typeof demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
Package last updated on 25 Jul 2025
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Related posts
Product
Socket Now Protects the Chrome Extension Ecosystem
Socket is launching experimental protection for Chrome extensions, scanning for malware and risky permissions to prevent silent supply chain attacks.
By Mix Irving, Alexandros Kapravelos, Eli Insua - Jul 30, 2025
Product
Introducing Socket MCP for Claude Desktop
Add secure dependency scanning to Claude Desktop with Socket MCP, a one-click extension that keeps your coding conversations safe from malicious packages.
By Alexandros Kapravelos - Jul 29, 2025