Module: util/type-checks

A module with functions that perform runtime type checks. There are very simple checks such as isString(), there also are complex checks.

Source:

Methods

(static) countEnumerableProperties(o) → {number}

Parameters:
Name Type Description
o object

An alternative to Object.keys(o).length that is more efficient. Running a test loop comparing the two showed less than half the time for the for-loop option. Also, Object.keys creates a temporary array.

Source:
Returns:

Type: number

(static) isEncoding(thing) → {boolean}

Parameters:
Name Type Description
thing *

Valid encodings for file streams are binary (undefined or null), "base64" and "utf8".

Source:
Returns:

Type: boolean

(static) isHash(thing) → {boolean}

Parameters:
Name Type Description
thing *

An argument that can be of any type

ONE uses SHA-256 hashes in hexadecimal lowercase format to represent the contents of files. This functions tests a given "thing" of any type if it is such a string.

For the curious: Why a function?

While one might simply test against a regular expression using myRegEx.test(thing) this method has one more or less theoretical problem: If the thing is an object with a toString() method that returns a matching string the test will return "true" even though the thing is an object and not a string. For example,

/^s+$/.test( {toString: () => 'sss'} );

will return true.

Source:
Returns:

True if the argument is a SHA-256 lowercase hexadecimal string, false if not

Type: boolean

(static) looksLikeHash(s) → {boolean}

Parameters:
Name Type Description
s *

Non-regex version of the "isHash" function in an attempt to save a tiny bit of CPU because we don't need a full regex check here. "Premature optimization" vs. "it's cheap and easy", and according to reported real world runtime experience these hash checks can add up and become significant.

Source:
Returns:

Type: boolean

(static) ensureHash(thing) → {SHA256Hash}

Parameters:
Name Type Description
thing *

The function returns the given value after making sure it is a SHA-256 hexadecimal string. It throws an Error if this is not the case.

Source:
Throws:
Error
Returns:

Type: SHA256Hash

(static) ensureIdHash(thing) → {SHA256Hash}

Parameters:
Name Type Description
thing *

The function returns the given value after making sure it is a SHA-256 hexadecimal string. It throws an Error if this is not the case.

Source:
Throws:
Error
Returns:

Type: SHA256Hash

(static) isEventSourceConsumer(thing) → {boolean}

Parameters:
Name Type Description
thing *

Checks if a given object is a ONE.core OneEventSourceConsumer object by testing the properties (duck typing).

Source:
Returns:

Type: boolean

(static) isEventSource(thing) → {boolean}

Parameters:
Name Type Description
thing *

Checks if a given object is a ONE.core OneEventSource object by testing the properties (duck typing).

Source:
Returns:

Type: boolean

(static) isSimpleReadStream(thing) → {boolean}

Parameters:
Name Type Description
thing *

Checks if a given object is a ONE.core SimpleReadStream object by testing the properties (duck typing).

Source:
Returns:

Type: boolean

(static) isFileCreationResult(thing) → {boolean}

Parameters:
Name Type Description
thing *

Checks for FileCreation objects. They are used to return the result of saving BLOBs and CLOBs to storage.

Source:
Returns:

Type: boolean

(static) ensureArrayOfSHA256Hash(thing) → {Array.<SHA256Hash>}

Parameters:
Name Type Description
thing *

Data e.g. from a network connection expected to be of format SHA256Hash[]
Source:
Throws:

Throws an Error when the given data is not an array of (only) SHA-256 hashes

Type: Error

Returns:

Returns the data now confirmed to be of type Array of SHA256Hash

Type: Array.<SHA256Hash>

(static) ruleHasItemType(obj) → {RecipeRule}

Parameters:
Name Type Description
obj RecipeRule
Source:
Returns:

Type: RecipeRule

(static) isListItemType(arg) → {boolean}

Parameters:
Name Type Description
arg ValueType

Check if the valueType is a list type: array, bag, or set.

Source:
Returns:

Type: boolean