sequence

Define custom 'number' sequences in a collection, using the nodejs number-sequence library, with optional prefix and suffix.

Introduction

This meteor library lets you define and use a your own sequence, which might be useful for order numbers, customer numbers etc.

Think 'autonumber' or 'auto_increment', but more flexible (albeit less efficient, of course).

You can define a sequence like 00129QXZ, LONDON-ORDER-ABC123*-DRAFT, or PREFIX-00123-SUFFIX, or a simple 'numeric' sequence (although this library is overkill if that's all you need).

Note: Be certain to make the sequence length larger than you are likely to need; Otherwise it will 'roll over' and you are likely to be left with duplicates.

Installation

meteor npm install number-sequence --save
meteor add juto:sequence

Usage

See examples below. You need to provide:

a number system, which is a set of 'digit' characters (as a string) in increasing order of significance, from left to right.
a numeric length, which is the number of 'digits' you will be maintaining in the sequence.
a padding character, to left-pad shorter sequences to the value you specified in the length parameter.
(optional) a string prefix to prepend to the sequence before returning.
(optional) a string suffix to append to the sequence before returning.

Example 1 : Two digits, decimal (base 10)

import sequence from 'meteor/juto:sequence'; 

// define a new 2-digit sequence and give it a name
sequence.newSequence(
  "twoDigitBaseTen", // sequence name (must be unique). 
  {
    numsys: "0123456789", // the 'digits' to be used in the sequence
    padChar: "0", // the character to left-pad with if the value is not long enough. 
    length: 2 // the number of characters in the sequence; the sequence will 'wrap around' if it runs out of values.
  },
  "00" // the initial value of the sequence
).then(function (id) {
  console.log(`created a new sequence with id ${id}`);
});

const numValues = sequence.calculateNumberOfPossibleValues("twoDigitBaseTen"); // 100 possible values, since we have 2 digits.

// get the next value in the sequence
sequence.getAndUpdateNextNumberInSequence("twoDigitBaseTen")
.then(function (nextInSequence) {
  console.log(nextInSequence); // 01
});

// get the next value in the sequence
sequence.getAndUpdateNextNumberInSequence("twoDigitBaseTen")
.then(function (nextInSequence) {
  console.log(nextInSequence); // 02
});

Example 2 : Two digits, hexadecimal (base 16)

Note that this time we're setting the initial value to 'EF' so that the next value should be 'F0'

// define a new 2-digit sequence and give it a name
sequence.newSequence(
  "hex", // sequence name (must be unique). 
  {
    numsys: "0123456789ABCDEF", // the 'digits' to be used in the sequence
    padChar: "0", // the character to left-pad with if the value is not long enough. 
    length: 2 // the number of characters in the sequence; the sequence will 'wrap around' if it runs out of values.
  },
  "EF" // the initial value of the sequence
).then(function (id) {
  console.log(`created a new sequence with id ${id}`);
});

const numValues = sequence.calculateNumberOfPossibleValues("hex"); // 256 possible values, since we have 2 digits.

// get the next value in the sequence
sequence.getAndUpdateNextNumberInSequence("hex")
.then(function (nextInSequence) {
  console.log(nextInSequence); // F0
});

// get the next value in the sequence
sequence.getAndUpdateNextNumberInSequence("hex")
.then(function (nextInSequence) {
  console.log(nextInSequence); // F1
});

Example 3 : Two digits, hexadecimal, with prefix and suffix (base 16)