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util

@prismatic-io/spectral › "util"

The util module provides a set of functions commonly needed to author custom components. Many functions in the util module are used to coerce data into a particular type, and can be accessed through util.types. For example, util.types.toInt("5.5") will return an integer, 5.

Index#

Functions#

Functions#

Const formatJsonExample#

▸ formatJsonExample(input: unknown): string

Defined in packages/spectral/src/util.ts:319

This function helps to format JSON examples for documentation.

Parameters:

NameTypeDescription
inputunknownAn object to be JSONified.

Returns: string

This function returns a code block that can be used for documentation.

Const isBigInt#

▸ isBigInt(value: unknown): value is bigint

Defined in packages/spectral/src/util.ts:143

Parameters:

NameTypeDescription
valueunknownThe value to test

Returns: value is bigint

This function returns true if the type of value is a bigint, or false otherwise.

Const isBool#

▸ isBool(value: unknown): value is boolean

Defined in packages/spectral/src/util.ts:24

Determine if a variable is a boolean (true or false).

  • util.types.isBool(false) will return true, since false is a boolean.
  • util.types.isBool("Hello") will return false, since "Hello" is not a boolean.

Parameters:

NameTypeDescription
valueunknownThe variable to test.

Returns: value is boolean

True if the value is a boolean, or false otherwise.

Const isBufferDataPayload#

▸ isBufferDataPayload(value: unknown): boolean

Defined in packages/spectral/src/util.ts:238

This function tests if the object provided is a Prismatic DataPayload object. A DataPayload object is an object with a data attribute, and optional contentType attribute.

Parameters:

NameTypeDescription
valueunknownThe value to test

Returns: boolean

This function returns true if value is a DataPayload object, and false otherwise.

Const isData#

▸ isData(value: unknown): boolean

Defined in packages/spectral/src/util.ts:298

deprecated This function tests if the object provided is a Prismatic DataPayload object. A DataPayload object is an object with a data attribute, and optional contentType attribute.

Parameters:

NameTypeDescription
valueunknownThe value to test

Returns: boolean

This function returns true if value is a DataPayload object, and false otherwise.

Const isDate#

▸ isDate(value: unknown): value is Date

Defined in packages/spectral/src/util.ts:169

This function returns true if value is a variable of type Date, and false otherwise.

Parameters:

NameType
valueunknown

Returns: value is Date

Const isInt#

▸ isInt(value: unknown): value is number

Defined in packages/spectral/src/util.ts:62

This function checks if value is an integer. util.types.isInt(5) returns true, while util.types.isInt("5") or util.types.isInt(5.5) returns false.

Parameters:

NameTypeDescription
valueunknownThe variable to test.

Returns: value is number

This function returns true or false, depending on if value is an integer.

Const isJSON#

▸ isJSON(value: string): boolean

Defined in packages/spectral/src/util.ts:348

This function returns true if value resembles the shape of JSON, and false otherwise.

  • isJSON(undefined) will return false`
  • isJSON(null) will return true`
  • isJSON("") will return false`
  • isJSON(5) will return true`
  • isJSON('{"name":"John", "age":30, "car":null}') will return true`

Parameters:

NameTypeDescription
valuestringThe value to test against

Returns: boolean

This function returns a boolean, dependant on whether value can be parsed to JSON.

Const isNumber#

▸ isNumber(value: unknown): boolean

Defined in packages/spectral/src/util.ts:112

Determine if a variable is a number, or can easily be coerced into a number.

  • util.types.isNumber(3.21) will return true, since 3.21 is a number.
  • util.types.isBool("5.5") will return true, since the string "5.5" can easily be coerced into a number.
  • util.types.isBool("Hello") will return false, since "Hello" is not a number.

Parameters:

NameTypeDescription
valueunknownThe variable to test.

Returns: boolean

This function returns true if value can easily be coerced into a number, and false otherwise.

Const isUrl#

▸ isUrl(value: string): boolean

Defined in packages/spectral/src/util.ts:206

This function tests if the string provided is a valid URL, and returns true if the URL is valid. Note: this function only tests that the string is a syntactically correct URL; it does not check if the URL is web accessible.

  • util.types.isUrl('https://prismatic.io') will return true.
  • util.types.isUrl('https:://prismatic.io') will return false due to the extraneous : symbol.

Parameters:

NameTypeDescription
valuestringThe URL to test.

Returns: boolean

This function returns true if value is a valid URL, and false otherwise.

Const keyValPairListToObject#

▸ keyValPairListToObject‹TValue›(kvpList: KeyValuePair‹unknown›[], valueConverter?: undefined | function): Record‹string, TValue›

Defined in packages/spectral/src/util.ts:218

This function helps to transform key-value lists to objects. This is useful for transforming inputs that are key-value collections into objects.

For example, an input that is a collection might return [{key: "foo", value: "bar"},{key: "baz", value: 5}]. If that array were passed into util.types.keyValPairListToObject(), an object would be returned of the form {foo: "bar", baz: 5}.

Type parameters:

▪ TValue

Parameters:

NameTypeDescription
kvpListKeyValuePair‹unknown›[]An array of objects with key and value properties.
valueConverter?undefined | functionOptional function to call for each value.

Returns: Record‹string, TValue›

Const lowerCaseHeaders#

▸ lowerCaseHeaders(headers: Record‹string, string›): Record‹string, string›

Defined in packages/spectral/src/util.ts:376

This function returns a lower cased version of the headers passed to it.

  • lowerCaseHeaders({"Content-Type": "Application/JSON"}) will return {"content-type": "Application/JSON"}
  • lowerCaseHeaders({"Cache-Control": "max-age=604800"}) will return {"cache-control": "max-age=604800"}
  • lowerCaseHeaders({"Accept-Language": "en-us"}) will return {"accept-language": "en-us"}

Parameters:

NameTypeDescription
headersRecord‹string, string›The headers to convert to lower case

Returns: Record‹string, string›

This function returns a header object

Const toBigInt#

▸ toBigInt(value: unknown): BigInt

Defined in packages/spectral/src/util.ts:156

This function coerces a provided value into a bigint if possible. The provided value must be a bigint, integer, string representing an integer, or a boolean.

  • util.types.toBigInt(3) will return 3n.
  • util.types.toBigInt("-5") will return -5n.
  • util.types.toBigInt(true) will return 1n (and false will return 0n).
  • util.types.toBigInt("5.5") will throw an error, as 5.5 is not an integer.

Parameters:

NameTypeDescription
valueunknownThe value to coerce to bigint.

Returns: BigInt

This function returns the bigint representation of value.

Const toBool#

▸ toBool(value: unknown, defaultValue?: undefined | false | true): boolean

Defined in packages/spectral/src/util.ts:39

Convert truthy (true, "t", "true", "y", "yes") values to boolean true, and falsy (false, "f", "false", "n", "no") values to boolean false. Truthy/falsy checks are case-insensitive.

In the event that value is undefined or an empty string, a default value can be provided. For example, util.types.toBool('', true) will return true.

Parameters:

NameTypeDescription
valueunknownThe value to convert to a boolean.
defaultValue?undefined | false | trueThe value to return if value is undefined or an empty string.

Returns: boolean

The boolean equivalent of the truthy or falsy value.

Const toBufferDataPayload#

▸ toBufferDataPayload(value: unknown): DataPayload

Defined in packages/spectral/src/util.ts:254

Many libraries for third-party API that handle binary files expect Buffer objects. This function helps to convert strings, Uint8Arrays, and Arrays to a data structure that has a Buffer and a string representing contentType.

You can access the buffer like this: const { data, contentType } = util.types.toBufferDataPayload(someData);

If value cannot be converted to a Buffer, an error will be thrown.

Parameters:

NameTypeDescription
valueunknownThe string, Buffer, Uint8Array, or Array to convert to a Buffer.

Returns: DataPayload

This function returns an object with two keys: data, which is a Buffer, and contentType, which is a string.

Const toData#

▸ toData(value: unknown): DataPayload

Defined in packages/spectral/src/util.ts:312

deprecated Many libraries for third-party API that handle binary files expect Buffer objects. This function helps to convert strings, Uint8Arrays, and Arrays to a data structure that has a Buffer and a string representing contentType.

You can access the buffer like this: const { data, contentType } = util.types.toData(someData);

If value cannot be converted to a Buffer, an error will be thrown.

Parameters:

NameTypeDescription
valueunknownThe string, Buffer, Uint8Array, or Array to convert to a Buffer.

Returns: DataPayload

This function returns an object with two keys: data, which is a Buffer, and contentType, which is a string.

Const toDate#

▸ toDate(value: unknown): Date

Defined in packages/spectral/src/util.ts:181

This function parses an ISO date if possible, or throws an error if the value provided cannot be coerced into a Date object.

  • util.types.toDate(new Date('1995-12-17T03:24:00')) will return Date('1995-12-17T09:24:00.000Z') since a Date object was passed in.
  • util.types.toDate('2021-03-20') will return Date('2021-03-20T05:00:00.000Z') since a valid ISO date was passed in.
  • parseISODate('2021-03-20-05') will throw an error since value was not a valid ISO date.

Parameters:

NameTypeDescription
valueunknownThe value to turn into a date.

Returns: Date

The date equivalent of value.

Const toInt#

▸ toInt(value: unknown, defaultValue?: undefined | number): number

Defined in packages/spectral/src/util.ts:76

This function converts a variable to an integer if possible. util.types.toInt(5.5) will return 5. util.types.toInt("20.3") will return 20.

In the event that value is undefined or an empty string, a default value can be provided. For example, util.types.toInt('', 1) will return 1.

This function will throw an exception if value cannot be coerced to an integer.

Parameters:

NameTypeDescription
valueunknownThe value to convert to an integer.
defaultValue?undefined | numberThe value to return if value is undefined, an empty string, or not able to be coerced.

Returns: number

This function returns an integer if possible.

Const toJSON#

▸ toJSON(value: unknown): string

Defined in packages/spectral/src/util.ts:362

This function accepts an arbitrary object/value and safely serializes it (handles cyclic references).

Parameters:

NameTypeDescription
valueunknownArbitrary object/value to serialize.

Returns: string

JSON serialized text that can be safely logged.

Const toNumber#

▸ toNumber(value: unknown, defaultValue?: undefined | number): number

Defined in packages/spectral/src/util.ts:127

This function coerces a value (number or string) into a number. In the event that value is undefined or an empty string, a defaultValue can be provided, or zero will be returned. If value is not able to be coerced into a number but is defined, an error will be thrown.

  • util.types.toNumber("3.22") will return the number 3.22.
  • util.types.toNumber("", 5.5) will return the default value 5.5, since value was an empty string.
  • util.types.toNumber(undefined) will return 0, since value was undefined and no defaultValue was given.
  • util.types.toNumber("Hello") will throw an error, since the string "Hello" cannot be coerced into a number.

Parameters:

NameTypeDescription
valueunknownThe value to turn into a number.
defaultValue?undefined | numberThe value to return if value is undefined or an empty string.

Returns: number

This function returns the numerical version of value if possible, or the defaultValue if value is undefined or an empty string.

Const toString#

▸ toString(value: unknown, defaultValue: string): string

Defined in packages/spectral/src/util.ts:334

This function converts a value to a string. If value is undefined or an empty string, an optional defaultValue can be returned.

  • util.types.toString("Hello") will return "Hello".
  • util.types.toString(5.5) will return "5.5".
  • util.types.toString("", "Some default") will return "Some Default".
  • util.types.toString(undefined) will return "".

Parameters:

NameTypeDefaultDescription
valueunknown-The value to convert to a string.
defaultValuestring""A default value to return if value is undefined or an empty string.

Returns: string

This function returns the stringified version fo value, or defaultValue in the case that value is undefined or an empty string.