🏄 get block contents between balanced pairs, eg: {} <a></a> or code fences
Support the development of Balanced-Pairs.
# NPM
npm install --save balanced-pairs
# Yarn
yarn add balanced-pairsAn "Uneven Pair" is a pair of varying block delimiters. For example: HTML tags.
- 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.newBodyproperty 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
const balance = require('balanced-pairs')
const content = 'Foo <div>bar <div>baz</div></div> qux.'
const result = balance(content, {
open: '<div>',
close: '</div>'
})
console.log(result.blocks)Result:
{
blocks: [{
start: 0,
end: 37,
depth: 0,
body: 'Foo <div>bar <div>baz</div></div> qux.',
root: true,
children: [{
start: 9,
end: 26,
depth: 1,
pre: 'Foo <div>',
body: 'bar <div>baz</div>',
post: '</div> qux.',
root: false,
delimiter: {
start: 4,
end: 32,
pre: 'Foo ',
body: '<div>bar <div>baz</div></div>',
post: ' qux.'
},
children: [{
start: 18,
end: 20,
depth: 2,
pre: 'Foo <div>bar <div>',
body: 'baz',
post: '</div></div> qux.',
root: false,
delimiter: {
start: 13,
end: 26,
pre: 'Foo <div>bar ',
body: '<div>baz</div>',
post: '</div> qux.'
},
children: []
}]
}]
}],
polygon: [],
mode: 'odd',
inside: [Function: inside],
levels: {
'1': [{
start: 9,
end: 26,
depth: 1,
pre: 'Foo <div>',
body: 'bar <div>baz</div>',
post: '</div> qux.',
root: false,
delimiter: {
start: 4,
end: 32,
pre: 'Foo ',
body: '<div>bar <div>baz</div></div>',
post: ' qux.'
},
children: [{
start: 18,
end: 20,
depth: 2,
pre: 'Foo <div>bar <div>',
body: 'baz',
post: '</div></div> qux.',
root: false,
delimiter: {
start: 13,
end: 26,
pre: 'Foo <div>bar ',
body: '<div>baz</div>',
post: '</div> qux.'
},
children: []
}]
}],
'2': [{
start: 18,
end: 20,
depth: 2,
pre: 'Foo <div>bar <div>',
body: 'baz',
post: '</div></div> qux.',
root: false,
delimiter: {
start: 13,
end: 26,
pre: 'Foo <div>bar ',
body: '<div>baz</div>',
post: '</div> qux.'
},
children: []
}]
},
list: [{
start: 18,
end: 20,
depth: 2,
pre: 'Foo <div>bar <div>',
body: 'baz',
post: '</div></div> qux.',
root: false,
delimiter: {
start: 13,
end: 26,
pre: 'Foo <div>bar ',
body: '<div>baz</div>',
post: '</div> qux.'
},
children: []
}, {
start: 9,
end: 26,
depth: 1,
pre: 'Foo <div>',
body: 'bar <div>baz</div>',
post: '</div> qux.',
root: false,
delimiter: {
start: 4,
end: 32,
pre: 'Foo ',
body: '<div>bar <div>baz</div></div>',
post: ' qux.'
},
children: [{
start: 18,
end: 20,
depth: 2,
pre: 'Foo <div>bar <div>',
body: 'baz',
post: '</div></div> qux.',
root: false,
delimiter: {
start: 13,
end: 26,
pre: 'Foo <div>bar ',
body: '<div>baz</div>',
post: '</div> qux.'
},
children: []
}]
}]
}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.
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:
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!]}}}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:
const balance = require('balanced-pairs')
const content = 'FOO ```BAR``` BAZ ```QUX```'
const result = balance(content, {
open: '```',
close: '```'
})
console.log(result.blocks)Result:
[ { 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] }