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A module to teach you how to module.
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# varsize-string
Varsize-string is a JavaScript CommonJS (node.js) package for working
with strings where the different characters have different sizes.
## Installation & Usage
With [npm](https://docs.npmjs.com/getting-started/installing-node) you can install and use the `varsize-string` like this:
```
$ npm install varsize-string --save
```
With the package being successfully installed you can create an instance like this:
```JavaScript
function charWidth(charCode, formerCharCode, inString, pos) {
/* in this example a-z (lower-case) is 0.8 the width of other characters */
return (charCode >= 97 && charCode <= 122 ) ? 0.8 : 1
}
var VarSizeString = require('varsize-string')
var str = new VarSizeString('ABCdef', charWidth)
var str2 = VarSizeString('abcDEF', charWidth) // You don't need to use `new`
```
## Application
The most important application of `varsize-string` is in combination with
[`wcsize`](https://github.com/martinheidegger/wcsize) that identifies the size of strings rendered in a common terminal,
see [`wcstring`](https://github.com/martinheidegger/wcstring) for a shorthand combination of both.
It can also be used in a (visual) web context to correctly `wrap` or `truncate` strings.
## Operations
On the instance you can apply a set of operations. Note that the following explanation uses `size` as an accumulated amount of width and `width` as a single-line `size`.
### `.width()`
Get the `size` of the widest line in the string.
### `.size()`
Get the `size` of the complete string.
### `.sizeBeforeFirst(search, [<int> startOffset])`
Analogous to [`String.indexOf`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf). Looks for the first occurance of `search`. Optionally takes `startOffset` which is the `size` of characters that have to happen before the search takes place (default=0).
### `.sizeBeforeLast(search, [<int> endOffset])`
Analogous to [`String.lastIndexOf`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf). Looks for the last occurance of `search`.
Optionally takes `endOffset` which is the size offset from the end of the string from which to search for `search`.
### `.substring(<int> startSize, [<int> endSize])`
Analogous to [`String.substring`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/substring). This method will return the **fully visible** characters between `startSize` and `endSize`. If `endSize` is not given it will assume a substring from `startSize` until the end of the string.
_However:_ **Unlike** `String.substring`, this method returns an object with the properties `size` and `string` in order to know the size of the substring.
Example:
```JavaScript
var vsstring = require('varsize-string')
vsstring('abcdef', charWidth).substring(0, 3) // {string: 'abc', size: 2.4}
```
### `.substr(<int> startSize, [<int> size])`
Equal to `.substring(startSize, startSize + size)`.
### `.truncate(<int> size, <varsize-string || String> suffix)`
Truncates the string after a size. Will append the given `suffix` to the string if it does exceed the size.
### `.pop()`
Removes the last character from the string and returns the new `.size()`.
### `.wrap(<int> width, [padding])`
Normalizes the string in order for all lines to fit within `width`.
Example:
```JavaScript
var vsstring = require('varsize-string')
vsstring('abcdef', charWidth).wrap(3) // 'abc\ndef'
vsstring('ab cd ef', charWidth).wrap(5) // 'ab cd\nef'
vsstring('ab cd ef', charWidth).wrap(3) // 'ab\ncd\nef'
```
#### Padding
The padding option takes a padding specification and applies it to the
wrapping process.
Example:
```JavaScript
var padding = {
first: {left: ' - ', right: ' '},
regular: {left: ' ', right: ' '}
}
vsstring('abcdefghijklmnop', charWidth).wrap(10, padding)
// - abcdef
// ghijkl
// mnop
```
There are a few shorthands to specifying the padding:
```JavaScript
padding = ' '
```
... is equals to ...
```JavaScript
{
first: ' ',
regular: ' '
}
```
... is equals to ...
```JavaScript
{
first: {left: ' ': right: undefined},
regular: {left: ' ': right: undefined}
}
```
Also you can preset left/right for both first and regular:
```JavScript
{
right: 'x',
first: {left: ' - '},
regular: {left: ' '}
}
```
... is equal to ...
```JavaScript
{
first: {left: ' - ', right: 'x'},
regular: {left: ' ', right: 'x'}
}
```
Note that the left/right presets override the first/regular specification:
```JavaScript
{
left: 'x',
first: '-',
regular: ' '
}
```
... is equal to ...
```JavaScript
{
first: {left: 'x', right: undefined},
regular: {left: 'x', right: undefined}
}
```
Also it supports a fallback to regular if first is missing:
```JavaScript
{
regular: {left: 'x', right: undefined}
}
```
... is equal to ...
```JavaScript
{
first: {left: 'x', right: undefined},
regular: {left: 'x', right: undefined}
}
```
### `vsstring.padding(characterLookup, [process], [width], padding)`
Turns a flexible padding definition into a clear padding definition. You can pass in an optional `process` variable to process the strings before they are being turned into varsizes-strings. You can also pass-in a `width` to make sure that the padding will not exceed the width of, say, a wrapped string.