chunk.js

function chunk(arr, size) {
    return arr.reduce(
        (newarr, _, i) => (i % size ? newarr : [...newarr, arr.slice(i, i + size)]),
        []
    )
}

chunk.ts

function chunk<T extends any[]>(arr: T, size: number) {
    return arr.reduce(
        (newarr, _, i) => (i % size ? newarr : [...newarr, arr.slice(i, i + size)]),
        [] as T[][]
    )
}

sample.ts

// https://www.typescriptlang.org/play?#code/GYVwdgxgLglg9mABBAFuA1gHgCqIKYAeUeYAJgM6ICGYAngNoC6AfABRUBOHAXItgDSJyMAF55eYEAFsARng4BKRAG8AsAChEWxBzxQQHJJw4A6XaRAQ8rDdruJWYPAHdjggPqCYSgLzMHMIgApEKieIgA-IhOrlyIvPQmSTFu1Fwm5AA2MFasMF6IANShYgqMCvy29lpM1JTYTExVWgoaAL4aGgD0XYgAtP709ACMggBMggDMjIL0ACyCAKyCAGwziPQA7IyMGhAI5HCZeCakeDIgAOasqBisI+NTgguIy4grgtvPCq2aGkA
function chunk<T extends any[]>(arr: T, size: number) {
    return arr.reduce(
        (newarr, _, i) => (i % size ? newarr : [...newarr, arr.slice(i, i + size)]),
        [] as T[][]
    )
}

// -> [[1, 2, 3], [4, 5, 6], [7]]
console.debug(chunk([1, 2, 3, 4, 5, 6, 7], 3))