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/**
* This splits a string on a top-level character.
*
* Regex doesn't support recursion (at least not the JS-flavored version).
* So we have to use a tiny state machine to keep track of paren placement.
*
* Expected behavior using commas:
* var(--a, 0 0 1px rgb(0, 0, 0)), 0 0 1px rgb(0, 0, 0)
* ─┬─ ┬ ┬ ┬
* x x x ╰──────── Split because top-level
* ╰──────────────┴──┴───────────── Ignored b/c inside >= 1 levels of parens
*
* @param {string} input
* @param {string} separator
*/
export function splitAtTopLevelOnly(input, separator) {
let stack = []
let parts = []
let lastPos = 0
let isEscaped = false
for (let idx = 0; idx < input.length; idx++) {
let char = input[idx]
if (stack.length === 0 && char === separator[0] && !isEscaped) {
if (separator.length === 1 || input.slice(idx, idx + separator.length) === separator) {
parts.push(input.slice(lastPos, idx))
lastPos = idx + separator.length
}
}
if (isEscaped) {
isEscaped = false
} else if (char === '\\') {
isEscaped = true
}
if (char === '(' || char === '[' || char === '{') {
stack.push(char)
} else if (
(char === ')' && stack[stack.length - 1] === '(') ||
(char === ']' && stack[stack.length - 1] === '[') ||
(char === '}' && stack[stack.length - 1] === '{')
) {
stack.pop()
}
}
parts.push(input.slice(lastPos))
return parts
}
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