@shelf/fast-chunk-string/lib/index.js

Chunk string into equal substrings with unicode support

import runes from 'runes';
function fastChunkString(original, { size, unicodeAware = false, }) {
    const str = original || '';
    if (str.length === 0) {
        return [];
    }
    if (!unicodeAware) {
        return getChunks(str, size);
    }
    return getChunksUnicode(str, size);
}
function getChunks(str, size) {
    const strLength = str.length;
    if (strLength === 0) {
        return [];
    }
    if (size >= strLength) {
        return [str];
    }
    const numChunks = Math.ceil(strLength / size);
    const chunks = new Array(numChunks);
    for (let index = 0, offset = 0; index < numChunks; index += 1, offset += size) {
        chunks[index] = str.substr(offset, size);
    }
    return chunks;
}
function getChunksUnicode(str, size) {
    const runeChars = runes(str);
    const runeCount = runeChars.length;
    if (runeCount === 0) {
        return [];
    }
    if (size >= runeCount) {
        return [str];
    }
    const numChunks = Math.ceil(runeCount / size);
    const chunks = new Array(numChunks);
    for (let index = 0, offset = 0; index < numChunks; index += 1, offset += size) {
        const start = Math.min(Math.floor(offset), runeCount);
        const end = Math.min(Math.floor(offset + size), runeCount);
        let chunk = '';
        for (let i = start; i < end; i += 1) {
            chunk += runeChars[i];
        }
        chunks[index] = chunk;
    }
    return chunks;
}
export default fastChunkString;