Balanced-Pairs

> 🏄 get block contents between balanced pairs, eg: {} \\ or code fences


Support the development of Balanced-Pairs.

Install

``bash


NPM

- Uneven pairs can be nested.
- Uneven pairs return:
+ A nested tree of blocks.
+ A linear array of blocks in the order they were closed.
+ A object containing blocks mapped to their depth.
- An inside(charPos) function that returns all the nested blocks that the character is within.
- Each block contains an updateBody() function that sets the .newBody property on each block
- Result has a .flatten() method, to turn the block tree back into a string, replacing the old content with the updated content

`js
const balance = require('balanced-pairs')

const content = 'Foo

console.log(result.blocks)
`

Result:

`js
{
blocks: [{
start: 0,
end: 37,
depth: 0,
body: 'Foo

Each block contains an updateBody() function that sets the .newBody property on each block.

Result has a .flatten() method, to turn the block tree back into a string, replacing the old content with the updated content

Note: flattening a block will remove it's delimiters within the parent.


`js
const source = '0{1}{2}3'
const result = balance(source, {
open: '{',
close: '}'
})

result.blocks[0].children[0].updateBody('x')
result.blocks[0].children[1].updateBody('y')
const flattened = result.flatten()
console.log(flattened) // '0xy3'
`

You can also flatten nested content:

`js
const source = '0{1{2{3{4}}}}'
const result = balance(source, {
open: '{',
close: '}'
})

// result.blocks[0] = the root block
const block4 = result.blocks[0]
.children[0]
.children[0]
.children[0]
.children[0]

block4.updateBody('[BEEP!]')

const flattened = result.flatten()
console.log(flattened) // 0{1{2{3[BEEP!]}}}
`

Even Pairs

An "Even Pair" is a pair of identical block delimiters. For example: a markdown code-fence.

- Even pairs do not nest.
- Even pairs return a linear array of blocks.
- Even pairs return a polygon that can be used to determine whether any character position is inside or outside of a block.
- An inside(charPos) function to check whether any character is within a block.

Example:

`js
const balance = require('balanced-pairs')

const content = 'FOO `BAR` BAZ `QUX`'

const result = balance(content, {
open: '`',
close: '`'
})

console.log(result.blocks)
`

Result:

`js
[ { start: 7,
end: 9,
pre: 'FOO `',
body: 'BAR',
post: '` BAZ `QUX`',
polygon: [ [ 7, -1 ], [ 10, -1 ], [ 10, 1 ], [ 7, 1 ], [ 7, -1 ] ],
delimiter:
{ start: 4,
end: 12,
pre: 'FOO ',
body: '`BAR`',
post: '` BAZ `QUX`' } },
{ start: 21,
end: 23,
pre: 'FOO `BAR` BAZ `',
body: 'QUX',
post: '`',
polygon: [ [ 21, -1 ], [ 24, -1 ], [ 24, 1 ], [ 21, 1 ], [ 21, -1 ] ],
delimiter:
{ start: 18,
end: 26,
pre: 'FOO `BAR` BAZ ',
body: '`QUX`',
post: '`' } } ],
polygon:
[ [ 7, -1 ],
[ 10, -1 ],
[ 10, 1 ],
[ 7, 1 ],
[ 7, -1 ],
[ 21, -1 ],
[ 24, -1 ],
[ 24, 1 ],
[ 21, 1 ],
[ 21, -1 ] ],
mode: 'even',
inside: [Function: inside] }
``