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- module.exports = balanced;
- function balanced(a, b, str) {
- if (a instanceof RegExp) a = maybeMatch(a, str);
- if (b instanceof RegExp) b = maybeMatch(b, str);
- var r = range(a, b, str);
- return r && {
- start: r[0],
- end: r[1],
- pre: str.slice(0, r[0]),
- body: str.slice(r[0] + a.length, r[1]),
- post: str.slice(r[1] + b.length)
- };
- }
- function maybeMatch(reg, str) {
- var m = str.match(reg);
- return m ? m[0] : null;
- }
- balanced.range = range;
- function range(a, b, str) {
- var begs, beg, left, right, result;
- var ai = str.indexOf(a);
- var bi = str.indexOf(b, ai + 1);
- var i = ai;
- if (ai >= 0 && bi > 0) {
- begs = [];
- left = str.length;
- while (i >= 0 && !result) {
- if (i == ai) {
- begs.push(i);
- ai = str.indexOf(a, i + 1);
- } else if (begs.length == 1) {
- result = [ begs.pop(), bi ];
- } else {
- beg = begs.pop();
- if (beg < left) {
- left = beg;
- right = bi;
- }
- bi = str.indexOf(b, i + 1);
- }
- i = ai < bi && ai >= 0 ? ai : bi;
- }
- if (begs.length) {
- result = [ left, right ];
- }
- }
- return result;
- }
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