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