Module: collection_helpers

Various helper methods for dealing with collections (arrays, objects, etc.)

Methods

(inner) addDicts(…dicts) → {StringNumberDict}

Adds up an arbitrary number of StringNumberDicts, returning a new dict.
Parameters:
Name Type Attributes Description
dicts Array.<StringNumberDict> <repeatable>
 Dictionaries to sum.
Returns:
The summed dictionary.
Type
StringNumberDict

(inner) asOptionalArray(value) → {ArArray}

Returns an array containing the value if defined, otherwise an empty array.
Parameters:
Name Type Description
value T | undefined | null The value to wrap.
Returns:
The optional array.
Type
ArArray

(inner) atLeastValues(obj, minValue) → {StringNumberDict}

Returns a new object with only the key/value pairs that have a value greater than minValue.
Parameters:
Name Type Description
obj StringNumberDict The input dictionary.
minValue number The minimum value to include.
Returns:
The filtered dictionary.
Type
StringNumberDict

(inner) average(values) → {number}

Calculates the average of an array of numbers, ignoring null/undefined completely.
Parameters:
Name Type Description
values Array.<number> The array of numbers.
Returns:
The average, or NaN if the array is empty.
Type
number

(async, inner) batchMap(array, fxn, optionsopt) → {Promise.<Array.<any>>}

Processes an array asynchronously in batches.
Parameters:
Name Type Attributes Description
array Array.<T> The array to process.
fxn function The async function to apply.
options object <optional>
 Batch options.
Properties
Name Type Attributes Description
batchSize number <optional>
 Batch size.
logger Logger <optional>
 Logger instance.
sleepBetweenMS number <optional>
 Sleep between batches in ms.
Returns:
The results of mapping items with fxn().
Type
Promise.<Array.<any>>

(inner) checkUniqueRows(array, logger)

Checks if the elements of an array have unique IDs and logs a warning if not.
Parameters:
Name Type Description
array Array.<ApiObjWithID> Array of objects with IDs.
logger Logger Logger to use for warnings.

(inner) computeMinMax(array, valueFxn) → {MinMax|null}

Computes the minimum and maximum values from an array using a value function.
Parameters:
Name Type Description
array Array.<T> The array to process.
valueFxn function Function to extract value.
Returns:
The min and max values, or null if array is empty.
Type
MinMax | null

(inner) countValues(items, getKeyopt, countNullsopt) → {StringNumberDict}

Returns a dictionary keyed by the result of getKey() with the count of each key.
Parameters:
Name Type Attributes Description
items Array.<T> The items to count.
getKey function <optional>
 Function to get key.
countNulls boolean <optional>
 Whether to count null keys.
Returns:
The counts dictionary.
Type
StringNumberDict

(inner) decrementCount(counts, kopt, incrementopt) → {StringNumberDict}

Decrements the count for a key in a dictionary.
Parameters:
Name Type Attributes Default Description
counts StringNumberDict The counts dictionary.
k CountKey | null <optional>
 The key to decrement.
increment number <optional>
 1 The decrement amount.
Returns:
The updated dictionary.
Type
StringNumberDict

(inner) filterWithLog(array, filterFxn, logger, reason, objTypeopt) → {Array.<T>}

Filters an array and logs the number of elements removed.
Parameters:
Name Type Attributes Description
array Array.<T> The array to filter.
filterFxn function The filter function.
logger Logger Logger instance.
reason string Reason for filtering.
objType string <optional>
 Object type for logging.
Returns:
The filtered array.
Type
Array.<T>

(inner) findMinMaxId(array) → {MinMaxID|null}

Finds the minimum and maximum 'id' property in an array of objects that have an 'id' property. Find the minimum 'id' property in an array of objects that have an 'id' property. TODO: Note that this isn't always safe to use - there can be outliers in the data that result in the minimum ID in a set of toots being wildly out of step with the rest of the IDs. If that happens trying to use the min ID as the maxId param for a fetch will fail (no results). This is an unfixable server side problem that we used to work around with this: static findMinIdForMaxIdParam(toots: Toot[]): string | null { if (toots.length == 0) return null; const idx = Math.min(toots.length - 1, MAX_ID_IDX); return sortByCreatedAt(toots)[idx].id; }
Parameters:
Name Type Description
array Array.<ApiObjWithID> Array of objects with IDs.
Returns:
The min and max IDs, or null if invalid.
Type
MinMaxID | null

(async, inner) getPromiseResults(promises) → {Promise.<PromisesResults.<T>>}

Collates the fulfilled and rejected results from Promise.allSettled() into an easier to handle format.
Parameters:
Name Type Description
promises Array Array of promises.
Returns:
The results object.
Type
Promise.<PromisesResults.<T>>

(inner) groupBy(array, makeKey) → {Record.<string, Array.<T>>}

Groups an array by the result of makeKey(). TODO: Standard library Object.groupBy() requires some tsconfig setting that i don't understand
Parameters:
Name Type Description
array Array.<T> The array to group.
makeKey function Function to get group key.
Returns:
The grouped object.
Type
Record.<string, Array.<T>>

(inner) incrementCount(counts, kopt, incrementopt) → {StringNumberDict}

Increments the count for a key in a dictionary by 'increment'.
Parameters:
Name Type Attributes Default Description
counts StringNumberDict The counts dictionary.
k CountKey | null <optional>
 The key to increment.
increment number <optional>
 1 The increment amount.
Returns:
The updated dictionary.
Type
StringNumberDict

(inner) isRecord(obj) → {boolean}

Return true if the object is a non-null object (not an array, function, etc.).
Parameters:
Name Type Description
obj unknown The object to check.
Returns:
True if it's a non-null object
Type
boolean

(inner) keyById(array) → {Record.<string, T>}

Builds a dictionary from an array keyed by id.
Parameters:
Name Type Description
array Array.<T> Array of objects with id property.
Returns:
The keyed dictionary.
Type
Record.<string, T>

(inner) keyByProperty(array, keyFxn) → {Record.<string, T>}

Builds a dictionary from an array keyed by a property.
Parameters:
Name Type Description
array Array.<T> Array of objects.
keyFxn function Function to get key.
Returns:
The keyed dictionary.
Type
Record.<string, T>

(inner) makeChunks(array, options) → {Array.<Array.<T>>}

Splits an array into chunks of a given size or number of chunks.
Parameters:
Name Type Description
array Array.<T> The array to chunk.
options object Chunk options.
Properties
Name Type Attributes Description
chunkSize number <optional>
 Size of each chunk.
logger Logger <optional>
 Logger instance.
numChunks number <optional>
 Number of chunks.
Returns:
The array of chunks.
Type
Array.<Array.<T>>

(inner) makePercentileChunks(array, fxn, numPercentiles) → {Array.<Array.<T>>}

Sorts an array by a function and divides into numPercentile chunks.
Parameters:
Name Type Description
array Array.<T> The array to sort and chunk.
fxn function Function to get value.
numPercentiles number Number of percentiles.
Returns:
The percentile chunks.
Type
Array.<Array.<T>>

(inner) reduceToCounts(objs, updateCounts) → {StringNumberDict}

Reduces an array to a StringNumberDict using an update function.
Parameters:
Name Type Description
objs Array.<T> The array to reduce.
updateCounts function Update function.
Returns:
The reduced dictionary.
Type
StringNumberDict

(inner) removeKeys(obj, keysToRemoveopt, keysToRemoveIfFalseopt) → {Partial.<T>}

Removes keys from an object if their value is null or in keysToRemove array.
Parameters:
Name Type Attributes Description
obj T The object to clean.
keysToRemove Array.<K> <optional>
 Keys to remove.
keysToRemoveIfFalse Array.<K> <optional>
 Keys to remove if value is false.
Returns:
The cleaned object.
Type
Partial.<T>

(async, inner) resolvePromiseDict(dict, logger) → {Promise.<Record.<string, any>>}

Use Promise.allSettled() to resolve a dictionary of promises in parallel.
Parameters:
Name Type Description
dict PromiseDict Dictionary of promises to resolve.
logger Logger Logger instance for logging errors.
Returns:
The cleaned object.
Type
Promise.<Record.<string, any>>

(inner) shuffle(array) → {Array.<T>}

Randomizes the order of an array.
Parameters:
Name Type Description
array Array.<T> The array to shuffle.
Returns:
The shuffled array.
Type
Array.<T>

(inner) sortKeysByValue(dict) → {Array.<string>}

Sorts the keys of a dictionary by their values in descending order.
Parameters:
Name Type Description
dict StringNumberDict The dictionary to sort.
Returns:
The sorted keys.
Type
Array.<string>

(inner) sortObjsByCreatedAt(array) → {Array.<T>}

Sorts an array of objects by the createdAt property.
Parameters:
Name Type Description
array Array.<T> The array to sort.
Returns:
The sorted array.
Type
Array.<T>

(inner) sortObjsByProps(array, prop, ascendingopt, ignoreCaseopt) → {Array.<T>}

Sorts an array of objects by one or two properties.
Parameters:
Name Type Attributes Description
array Array.<T> The array to sort.
prop Array Property or properties to sort by.
ascending boolean | Array.<boolean> <optional>
 Sort order(s).
ignoreCase boolean <optional>
 Ignore case for string properties.
Returns:
The sorted array.
Type
Array.<T>

(inner) split(array, condition) → {Array.<Array.<T>>}

Splits an array into two arrays based on a condition.
Parameters:
Name Type Description
array Array.<T> The array to split.
condition function The condition function.
Returns:
The two arrays.
Type
Array.<Array.<T>>

(inner) subtractConstant(dict, constant) → {StringNumberDict}

Subtracts a constant from all values in a dictionary.
Parameters:
Name Type Description
dict StringNumberDict The dictionary.
constant number The constant to subtract.
Returns:
The updated dictionary.
Type
StringNumberDict

(inner) sumArray(array) → {number}

Sums the elements of an array, treating null/undefined as 0.
Parameters:
Name Type Description
array Array.<OptionalNumber> The array to sum.
Returns:
The sum.
Type
number

(inner) sumValues(obj) → {number}

Sums the values of a dictionary.
Parameters:
Name Type Description
obj StringNumberDict | Weights The dictionary.
Returns:
The sum.
Type
number

(inner) swapKeysAndValues(dict) → {StringDict}

Swaps the keys and values of a dictionary.
Parameters:
Name Type Description
dict T The dictionary.
Returns:
The swapped dictionary.
Type
StringDict

(inner) transformKeys(data, transform) → {T}

Recursively applies a transform function to all keys in a nested object.
Parameters:
Name Type Description
data T The data to transform.
transform function The transform function.
Returns:
The transformed data.
Type
T

(inner) truncateToConfiguredLength(array, maxRecords, loggeropt) → {Array.<T>}

Truncates an array to a maximum length, logging if truncated.
Parameters:
Name Type Attributes Description
array Array.<T> The array to truncate.
maxRecords number The maximum length.
logger Logger <optional>
 Logger instance.
Returns:
The truncated array.
Type
Array.<T>

(inner) uniquify(array) → {Array.<string>|undefined}

Returns a new array with only unique, non-null string values.
Parameters:
Name Type Description
array Array The array to uniquify.
Returns:
The unique array or undefined if empty.
Type
Array.<string> | undefined

(inner) uniquifyApiObjs(cacheKey, array, logger)

Uniquify an array of API objects by the appropriate property. This is a no-op for API objects that don't have a property that can be used to uniquely identify them.
Parameters:
Name Type Description
cacheKey ApiCacheKey The cache key to determine the unique property.
array Array.<T> Array of API objects.
logger Logger Logger to use for warnings.

(inner) uniquifyByProp(rows, transform, logPrefixopt) → {Array.<T>}

Removes elements of an array with duplicate values for a given property.
Parameters:
Name Type Attributes Description
rows Array.<T> The array to uniquify.
transform function Function to get property.
logPrefix string <optional>
 Log prefix.
Returns:
The uniquified array.
Type
Array.<T>

(inner) zipArrays(array1, array2) → {Record.<string, T>}

Zips two arrays into a dictionary ([ 'a', 'b', 'c' ], [ 1, 2, 3 ] -> { a: 1, b: 2, c: 3 })
Parameters:
Name Type Description
array1 Array.<string> Keys array.
array2 Array.<T> Values array.
Returns:
The zipped dictionary.
Type
Record.<string, T>

(async, inner) zipPromiseCalls(args, promiser, loggeropt) → {Promise.<Record.<string, T>>}

Runs a list of promises in parallel, each generated by a call to promiser(arg), and returns a dict of results keyed by input. Raises error on isAccessTokenRevokedError(), otherwise just logs a warning and moves on.
Parameters:
Name Type Attributes Description
args Array.<string> The keys.
promiser function The promise function.
logger Logger <optional>
 Logger instance.
Returns:
The results dictionary.
Type
Promise.<Record.<string, T>>