Created
February 14, 2023 22:06
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JS: Valid String Closures.
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| /* | |
| Return TRUE or FALSE whether the string has valid closures. | |
| A valid closure can be: () or ({}) or []({}). | |
| An invalid closure interrupts open/close characters. | |
| Each opener character must have a closer character. | |
| Each closer character must have an opener character. | |
| */ | |
| const patterns = { | |
| '{': '}', | |
| '[': ']', | |
| '(': ')', | |
| } | |
| const validPattern = str => { | |
| let invalid = false | |
| const arr = str.split('') | |
| const openers = Object.keys(patterns) | |
| const closers = Object.values(patterns) | |
| const o = [] | |
| const c = [] | |
| arr.map((char, i) => { | |
| if (openers.includes(char)) o.push(char) | |
| if (closers.includes(char)) c.push(char) | |
| const prev = arr[i - 1] | |
| const next = arr[i + 1] | |
| const openIndex = openers.findIndex(i => i === prev) | |
| const closeIndex = closers.findIndex(i => i === next) | |
| if (openers.includes(prev) && closers.includes(next) && openIndex === closeIndex) { | |
| invalid = true | |
| } | |
| }) | |
| if (invalid) return false | |
| return (o.length !== c.length) ? false : true | |
| } | |
| console.log(validPattern('{([])}')) // TRUE | |
| console.log(validPattern('{}[]()')) // TRUE | |
| console.log(validPattern('{()}[]')) // TRUE | |
| console.log(validPattern('[)]')) // FALSE | |
| console.log(validPattern('{[]}(')) // FALSE | |
| console.log(validPattern('}{}')) // FALSE | |
| console.log(validPattern('{[]')) // FALSE | |
| console.log(validPattern('{[(])]}')) // FALSE | |
| console.log(validPattern('[(])')) // FALSE |
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