count-uniq-strings

Count occurrences of strings, and record the order of their first occurrence.

API

countUniqStrings([thing1[, thing2[, …]]])

The module exports this function. It creates and returns a new accumulator accum. If things are passed, they're .add()ed to it.

An accumulator is an array that records the order of first encounters of each string, by appending it then. Future encounters of the same string will just increase the counter (see below).

accum.add([thing1[, thing2[, …]]])

Adds all things to accum, by one of these ways:

• ignore check: If the thing is null or undefined, it will be ignored.
• object check: If the thing is an object (including arrays), maybe its content is added.
  • array encounter: If an object's length property is a finite, positive number, its array-like content is .add()ed.
• string encounter: If the thing is not an object, its string value is encountered.

Always returns the accumulator.

accum.cnt

An object with no prototype (thus no inherited properties) that maps the strings to the number of encounters. The numbers will start with 1 on the first encounter, so unknown strings (keys) will be undefined.

Since there are no inherited properties, you can just test the truthiness of any key to check whether that string was encountered yet.

accum.prepare

If set, .add() uses it as a function to convert any value that it won't ignore, before the object check. After conversion, a 2nd ignore check is done, but no 2nd prepare().

accum.lower

If truthy, to-be-encountered string will be .toLowerCase()d first.

Usage

see usage.js

License

ISC