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util.types
util.types provides type checks for different kinds of built-in objects. Unlike instanceof or Object.prototype.toString.call(value), these checks do not inspect properties of the object that are accessible from JavaScript (like their prototype), and usually have the overhead of calling into C++.
The result generally does not make any guarantees about what kinds of properties or behavior a value exposes in JavaScript. They are primarily useful for addon developers who prefer to do type checking in JavaScript.
Methods 36
Returns true if the value is a built-in ArrayBuffer or SharedArrayBuffer instance.
See also util.types.isArrayBuffer() and util.types.isSharedArrayBuffer().
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is an arguments object.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in ArrayBuffer instance. This does not include SharedArrayBuffer instances. Usually, it is desirable to test for both; See util.types.isAnyArrayBuffer() for that.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is an instance of one of the ArrayBuffer views, such as typed array objects or DataView. Equivalent to ArrayBuffer.isView().
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is an async function. This only reports back what the JavaScript engine is seeing; in particular, the return value may not match the original source code if a transpilation tool was used.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a Bigint64Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a BigUint64Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a boolean object, e.g. created by new Boolean().
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is any boxed primitive object, e.g. created by new Boolean(), new String() or Object(Symbol()).
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in DataView instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Date instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Float32Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Float64Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a generator function. This only reports back what the JavaScript engine is seeing; in particular, the return value may not match the original source code if a transpilation tool was used.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a generator object as returned from a built-in generator function. This only reports back what the JavaScript engine is seeing; in particular, the return value may not match the original source code if a transpilation tool was used.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Int16Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Int32Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Int8Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Map instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is an iterator returned for a built-in Map instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is an instance of a built-in Error type.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a number object, e.g. created by new Number().
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Promise.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a regular expression object.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Set instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is an iterator returned for a built-in Set instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in SharedArrayBuffer instance. This does not include ArrayBuffer instances. Usually, it is desirable to test for both; See util.types.isAnyArrayBuffer() for that.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a string object, e.g. created by new String().
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a symbol object, created by calling Object() on a Symbol primitive.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in TypedArray instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Uint16Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Uint32Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Uint8Array instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in Uint8ClampedArray instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in WeakMap instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |
Returns true if the value is a built-in WeakSet instance.
| Parameters | Type | Description |
|---|---|---|
| value | any | value to check |