json-joy/esm/json-ot/types/ot-binary-irreversible/apply.js

Collection of libraries for building collaborative editing apps.

export const apply = (val, op) => {
    const length = op.length;
    let offset = 0;
    const res = [];
    let outputLength = 0;
    for (let i = 0; i < length; i++) {
        const component = op[i];
        switch (typeof component) {
            case 'object':
                res.push(component);
                outputLength += component.length;
                break;
            case 'number': {
                if (component > 0) {
                    const end = offset + component;
                    res.push(val.subarray(offset, end));
                    outputLength += end - offset;
                    offset = end;
                }
                else
                    offset -= component;
                break;
            }
        }
    }
    res.push(val.subarray(offset));
    outputLength += val.length - offset;
    const output = new Uint8Array(outputLength);
    const resLength = res.length;
    for (let i = 0, j = 0; i < resLength; i++) {
        const component = res[i];
        output.set(component, j);
        j += component.length;
    }
    return output;
};