node-utils
A collection of utility functions I find myself needing across multiple projects
Functions can be required
individually like so: const fn = require('@ack_inc/utils/lib/<fn-name-in-kebab-case>')
Docs
generateRandomString(nChars, constraints)
Generates a string of length nChars
that satisfies constraints
Use case: password or temporary token generation
Parameters
Name | Type | Required? | Description | Default | Comments |
---|---|---|---|---|---|
nChars | number | Y | The length of the string to generate | Must be a whole number. | |
constraints | object | N | Object specifying what characters can be in the generated string. | {} |
constraints
may have the following keys:
Key | Type | Effect |
---|---|---|
lowercase | Boolean | If true , include lowercase characters |
uppercase | Boolean | If true , include uppercase chracters |
digits | Boolean | If true , include digits |
symbols | Boolean | If true , include symbols |
If constraints
has none of the above keys, it is assumed that all characters are allowed
Look in lib/generate-random-string.js
for the full list of symbols used
Return value
Type | Description |
---|---|
string | The random string |
Usage
const { generateRandomString: rsg } = require('@ack_inc/utils');
console.log(rsg(<anything but a whole number>)); //=> throws TypeError
console.log(rsg(0)); //=> ""
console.log(rsg(5)); //=> "3`8aE"
console.log(rsg(5, { lowercase: true })); //=> "fewjk"
console.log(rsg(5, { lowercase: true, uppercase: true, digits: true, symbols: true })); //=> "%q31G"
groupByMultiKeys(records, getKeys)
Group an array of records into an array of sub-arrays of records. Records go into the same sub-array ("group") if any of the keys generated by getKeys are ===
equal
Use case: you have an array of records (of people, say); the records are from multiple sources, and you want to merge records (for belonging to the same person) if any of several different "identifiers" (email, phone number, social media handle, etc.) match
Parameters
Name | Type | Required? | Description | Default | Comments |
---|---|---|---|---|---|
records | Array<object> | Y | Array of records to group | A TypeError is thrown if records is not an array with at least one element |
|
getKeys | Function | Y | Function to generate keys for each record | Should take a record as the sole param, and return a single key or array of keys; signature is getKeys(record: object): Array<T>
|
Return value
Type | Description |
---|---|
Array<Array<object>> | Each element of the returned array is a group of records for which at least one key matched |
It may not be the case that there is a common key for all the records in a group. Further, there may be two records in a group that have no keys in common. For example, the following three records will be in the same group, through A
and C
do not have a common key, because they each have a key in common with another record in the group:
- Record
A
with keys ['a', 'b'] - Record
B
with keys ['b', 'c'] - Record
C
with keys ['c', 'd']
Usage
See the tests in lib/group-by-multi-keys.test.js
for usage examples
formatMobileNumber(mobileNumber, formatString)
Format a mobile number (must include country code) in different ways
Parameters
Name | Type | Required? | Description | Default | Comments |
---|---|---|---|---|---|
mobileNumber | string | Y | The mobile number to be formatted | An error is thrown if mobileNumber does not contain country code |
|
formatString | string | N | String describing how the provided mobile number should be formatted | "+CASR" |
In formatString
, only the following characters will be transformed:
Character | Transformed into |
---|---|
C | country code |
A | area code (first 3 digits after country code) |
S | subscriber number (next 3 digits) |
R | remaining digits |
Any other characters will appear as-is in the returned string
Return value
Type | Description |
---|---|
string | The formatted mobile number |
Usage
const { formatMobileNumber: format } = require('@ack_inc/utils');
console.log(format(<anything but a mobile number with country code>)); //=> throws Error
const mobile = "+1 123 456 7890";
expect(format(mobile)).toEqual("+11234567890");
expect(format(mobile, "+CASR")).toEqual("+11234567890");
expect(format(mobile, "+C A S R")).toEqual("+1 123 456 7890");
expect(format(mobile, "+C (A) S-R")).toEqual("+1 (123) 456-7890");
buildArr(n, generatorFn)
Format a mobile number (must include country code) in different ways
Parameters
Name | Type | Required? | Description | Default | Comments |
---|---|---|---|---|---|
n | number | Y | The number of elements in the created array | ||
generatorFn | function | N | Function that controls the values of the elements in the created array | x => x |
Return value
Type | Description |
---|---|
array | The built array |
Usage
const { buildArr } = require('@ack_inc/utils');
expect(buildArr(0)).toEqual([]);
expect(buildArr(2)).toEqual([0, 1]);
expect(buildArr(2, idx => idx + 1)).toEqual([1, 2]);
groupBy(records, groupFn)
Group records according to groupFn
Parameters
Name | Type | Required? | Description | Default | Comments |
---|---|---|---|---|---|
records | Array<record> | Y | The records to be grouped | ||
groupFn | function | N | Function that determines whether two records belong in the same group | (a, b) => false |
A record
is any object with an id
key
Return value
Type | Description |
---|---|
Array<Array<record>> | Each sub-array in the returned array is one group |
Usage
- See group-by.test.js
To Do
-
Automated documentation generation
-
Improve
generateRandomString
- Constraint: whitelisted chars
- Constraint: blacklisted chars
- Constraint: symbols that can be part of a url-component (See SO answer)