array-group-str-omit-num-char^3.0.3

Groups array of strings by omitting number characters

Install via npm

npm i array-group-str-omit-num-char

The default is exported, so instead of groupStr below, you can name the consumed function however you want.

Consume via a require():

const groupStr = require("array-group-str-omit-num-char");

or as an ES Module:

import groupStr from "array-group-str-omit-num-char";

Install as a script, via CDN

Put this in your HTML:

<script src="https://cdn.jsdelivr.net/npm/array-group-str-omit-num-char/dist/array-group-str-omit-num-char.umd.js">

Then, you’ll get a global variable arrayGroupStrOmitNumChar in your Global object and you consume it like this:

const groupStr = arrayGroupStrOmitNumChar;

This groupStr is your main function. See its API in the main section.

Trivia

This program has 43 assertions in its unit tests. That's less than all unit test assertions' median (50) and less than geometric mean (70).

§ Quick Take

import { strict as assert } from "assert";
import groupStr from "array-group-str-omit-num-char";

assert.deepEqual(
  groupStr(["a1-1", "a2-2", "b3-3", "c4-4"]),
  {
    "a*-*": 2,
    "b3-3": 1,
    "c4-4": 1,
  }
);

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§ Idea

Take an array of strings, group those which differ only by a certain number.

For example, consider this array atomic CSS class names coming from some report (for example, email-comb output object's key deletedFromHead):

[
  "wbr425-padding-top-1",
  "wbr425-padding-top-2",
  "main-title",
  "wbr425-padding-top-3",
];

In real life, you could have for example, wbr425-padding-top-* would be shorter and go up to 500 and there were, let's say, 20 other groups like it.

This npm library groups strings, in this case producing:

{
  "wbr425-padding-top-*": 3,
  "main-title": 1
}

Notice the "425" in wbr425 was not replaced with wildcard because it was constant on all strings that were grouped. This feature, retaining constant digits, was the reason why we got into hassle producing this library.

You see, the quickest, alternative (gung-ho) algorithm is to replace all digits with "*" and filter the unique values, but "425" in wbr425 would be lost. That's why we need this library.

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§ API

groupStr(sourceArray, [opts])

In other words, that variable you imported, "groupStr" (or "brambles" or whatever) is a function which consumes two input arguments.

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§ API - Input

Input argument	Type	Obligatory?	Description
`sourceArray`	Array	yes	Array of zero or more strings
`otps`	Plain object	no	An Optional Options Object. See its API below.

By the way, none of the input arguments are mutated.

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§ API - Output

An empty array input will give output of a empty plain object. A non-empty array (with at least one string inside) will yield a plain object: strings will be grouped and put as keys, they count will be put as integer values.

For example:

console.log(groupStr(["a1-1", "a2-2", "b3-3", "c4-4"]));
// {
//   "a*-*": 2,
//   "b3-3": 1,
//   "c4-4": 1
// }

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§ An Optional Options Object

Type: object - an Optional Options Object.

`options` object's key	Type	Default	Description
`wildcard`	String	`*`	What to use to mark grouped characters
`dedupePlease`	Boolean	`true`	By default, input array's contents will be deduped. But that's at a cost of performance, so if you're 100% sure your strings will be unique, set it to `false`.

Here are all defaults in one place for copying:

{
  wildcard: "*",
  dedupePlease: true
}

To explicitly mark the refusal to set custom Optional Options, it can be also passed as a null or undefined value. In that case, defaults will be set.

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