strind/lib/strind.js

Partition strings based on character indices

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/**
 * Partitions a string based on character indices.
 *
 * @param {string} str - string to partition
 * @param {[number,number][]} indices - array of tuples to match [start, end] indices
 * @param {function} callback - callback function called with matching characters
 */
function strind(str, indices, callback) {
    var strs = str.split('');
    var strsLen = strs.length;
    var idx = Array.isArray(indices[0]) ? indices : [indices];
    var partition = [];
    var nonmatched = [];
    function updateNonmatched(open, close, index) {
        var chars = str.slice(open, close);
        if (!chars.length) {
            return;
        }
        nonmatched.push({ chars: chars, index: index });
        if (callback) {
            var cb = callback({ chars: chars, matches: false });
            partition.push(cb);
        }
    }
    for (var i = 0, len = idx.length; i < len; i++) {
        var _a = idx[i], start = _a[0], end = _a[1];
        var floor = start >= 0 ? start : 0;
        var ceiling = end >= strsLen ? strsLen : end + 1;
        if (i === 0 && start > 0) {
            updateNonmatched(0, start, 0);
        }
        var chars = str.slice(floor, ceiling);
        if (callback) {
            var cb = callback({ chars: chars, matches: true });
            partition.push(cb);
        }
        else {
            partition.push(chars);
        }
        if (end < strsLen) {
            var open = end + 1;
            var close = i < len - 1 ? idx[i + 1][0] : strsLen;
            updateNonmatched(open, close, partition.length);
        }
        if (end >= strsLen) {
            break;
        }
    }
    return {
        unmatched: nonmatched,
        matched: partition
    };
}
exports.default = strind;