Function diff

npm/deno_asserts@0.168.0.mjs:85–232

(A, B)

    return common;
}
function diff(A, B) {
    const prefixCommon = createCommon(A, B);
    const suffixCommon = createCommon(A.slice(prefixCommon.length), B.slice(prefixCommon.length), true).reverse();
    A = suffixCommon.length ? A.slice(prefixCommon.length, -suffixCommon.length) : A.slice(prefixCommon.length);
    B = suffixCommon.length ? B.slice(prefixCommon.length, -suffixCommon.length) : B.slice(prefixCommon.length);
    const swapped = B.length > A.length;
    [A, B] = swapped ? [
        B,
        A
    ] : [
        A,
        B
    ];
    const M = A.length;
    const N = B.length;
    if (!M && !N && !suffixCommon.length && !prefixCommon.length) return [];
    if (!N) {
        return [
            ...prefixCommon.map((c)=>({
                    type: DiffType.common,
                    value: c
                })),
            ...A.map((a)=>({
                    type: swapped ? DiffType.added : DiffType.removed,
                    value: a
                })),
            ...suffixCommon.map((c)=>({
                    type: DiffType.common,
                    value: c
                }))
        ];
    }
    const offset = N;
    const delta = M - N;
    const size = M + N + 1;
    const fp = Array.from({
        length: size
    }, ()=>({
            y: -1,
            id: -1
        }));
    const routes = new Uint32Array((M * N + size + 1) * 2);
    const diffTypesPtrOffset = routes.length / 2;
    let ptr = 0;
    let p = -1;
    function backTrace(A, B, current, swapped) {
        const M = A.length;
        const N = B.length;
        const result = [];
        let a = M - 1;
        let b = N - 1;
        let j = routes[current.id];
        let type = routes[current.id + diffTypesPtrOffset];
        while(true){
            if (!j && !type) break;
            const prev = j;
            if (type === 1) {
                result.unshift({