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index.js
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index.js
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const escape = require("escape-string-regexp");
function filterTokens(string, opening, closing) {
let validTokens = new RegExp(
[...opening, ...closing]
.map(e => {
if (e instanceof RegExp) {
let stringified = e.toString();
return stringified.substring(1, stringified.length - 1);
} else {
return escape(e);
}
})
.join("|"),
"gm"
);
let elements = [];
let token;
while ((token = validTokens.exec(string)) !== null) {
elements.push(token[0].trim());
}
return elements;
}
function findOpening(element, opening) {
let found = false;
for (let token of [...opening]) {
if (token instanceof RegExp) {
if (element.match(token)) found = true;
} else {
if (token === element) found = true;
}
}
return found;
}
/**
* Search for matching pairs in a string.
*
* @param {string} string - The data that should be checked
* @param {string|Array} [opening] - Valid opening characters / words
* @param {string|Array} [closing] - Valid closing characters / words
* @returns {boolean}
*/
module.exports = function(string, opening = ["("], closing = [")"]) {
let stack = [];
let balanced = true;
let elements = filterTokens(string, opening, closing);
for (element of elements) {
if (findOpening(element, opening)) {
stack.push(element);
} else {
if (stack.length === 0) {
balanced = false;
} else {
stack.pop();
}
}
}
return balanced && stack.length === 0;
};