สมมติว่าเรามีอาร์เรย์ที่อธิบายดังนี้ −
const arr = [
{
"Arts": [
{
"Performing arts": [
{
"Music": [
{ "title": "Accompanying" },
{ "title": "Chamber music" },
{ "title": "Church music" },
{ "Conducting": [
{ "title": "Choral conducting" },
{ "title": "Orchestral conducting" },
{ "title": "Wind ensemble conducting" }
] },
{ "title": "Early music" },
{ "title": "Jazz studies" },
{ "title": "Musical composition" },
{ "title": "Music education" },
{ "title": "Music history" },
{ "Musicology": [
{ "title": "Historical musicology" },
{ "title": "Systematic musicology" }
] },
{ "title": "Ethnomusicology" },
{ "title": "Music theory" },
{ "title": "Orchestral studies" },
{ "Organology": [
{ "title": "Organ and historical keyboards" },
{ "title": "Piano" },
{ "title": "Strings, harp, oud, and guitar" },
{ "title": "Singing" },
{ "title": "Strings, harp, oud, and guitar" }
] },
{ "title": "Recording" }
] },
{ "Dance": [
{ "title": "Choreography" },
{ "title": "Dance notation" },
{ "title": "Ethnochoreology" },
{ "title": "History of dance" }
] },
{ "Television": [
{ "title": "Television studies" }
] },
{ "Theatre": [
{ "title": "Acting" },
{ "title": "Directing" },
{ "title": "Dramaturgy" },
{ "title": "History" },
{ "title": "Musical theatre" },
{ "title": "Playwrighting" },
{ "title": "Puppetry" }
] }
]
}]
}]; เราจำเป็นต้องเขียนฟังก์ชัน JavaScript ที่รับอาร์เรย์ดังกล่าว จากนั้นฟังก์ชันควรเพิ่มฟิลด์ "id" ในออบเจกต์ทั้งหมดที่มีฟิลด์ "title"
ค่าของคุณสมบัติ "id" ไม่ได้มีความสำคัญมากนัก (อาจเป็นค่าเฉพาะใดๆ ก็ได้) สิ่งที่สำคัญกว่าคือออบเจกต์ทั้งหมดที่มีคุณสมบัติ "title" จะต้องมีคุณสมบัติ "id"
เราต้องทำสิ่งนี้โดยไม่สร้างสำเนาของอาร์เรย์จริง
ตัวอย่าง
รหัสสำหรับสิ่งนี้จะเป็น −
const arr = [
{ "Arts": [
{ "Performing arts": [
{ "Music": [
{ "title": "Accompanying" },
{ "title": "Chamber music" },
{ "title": "Church music" },
{ "Conducting": [
{ "title": "Choral conducting" },
{ "title": "Orchestral conducting" },
{ "title": "Wind ensemble conducting" }
] },
{ "title": "Early music" },
{ "title": "Jazz studies" },
{ "title": "Musical composition" },
{ "title": "Music education" },
{ "title": "Music history" },
{ "Musicology": [
{ "title": "Historical musicology" },
{ "title": "Systematic musicology" }
] },
{ "title": "Ethnomusicology" },
{ "title": "Music theory" },
{ "title": "Orchestral studies" },
{ "Organology": [
{ "title": "Organ and historical keyboards" },
{ "title": "Piano" },
{ "title": "Strings, harp, oud, and guitar" },
{ "title": "Singing" },
{ "title": "Strings, harp, oud, and guitar" }
] },
{ "title": "Recording" }
] },
{ "Dance": [
{ "title": "Choreography" },
{ "title": "Dance notation" },
{ "title": "Ethnochoreology" },
{ "title": "History of dance" }
] },
{ "Television": [
{ "title": "Television studies" }
] },
{ "Theatre": [
{ "title": "Acting" },
{ "title": "Directing" },
{ "title": "Dramaturgy" },
{ "title": "History" },
{ "title": "Musical theatre" },
{ "title": "Playwrighting" },
{ "title": "Puppetry" }
] }
]
}]
}];
const addId = (id = 1) => {
return function recur(obj) {
if ('title' in obj) {
obj.id = id++;
};
Object.keys(obj).forEach(el => {
Array.isArray(obj[el]) && obj[el].forEach(recur);
});
};
}
const mapId = arr => {
arr.forEach(addId);
}
mapId(arr);
console.log(JSON.stringify(arr, undefined, 4)); ผลลัพธ์
และผลลัพธ์ในคอนโซลจะเป็น −
[
{
"Arts": [
{
"Performing arts": [
{
"Music": [
{
"title": "Accompanying"
},
{
"title": "Chamber music"
},
{
"title": "Church music"
},
{
"Conducting": [
{
"title": "Choral conducting"
},
{
"title": "Orchestral conducting"
},
{
"title": "Wind ensemble conducting"
}
]
},
{
"title": "Early music"
},
{
"title": "Jazz studies"
},
{
"title": "Musical composition"
},
{
"title": "Music education"
},
{
"title": "Music history"
},
{
"Musicology": [
{
"title": "Historical musicology"
},
{
"title": "Systematic musicology"
}
]
},
{
"title": "Ethnomusicology"
},
{
"title": "Music theory"
},
{
"title": "Orchestral studies"
},
{
"Organology": [
{
"title": "Organ and historical keyboards"
},
{
"title": "Piano"
},
{
"title": "Strings, harp, oud, and guitar"
},
{
"title": "Singing"
},
{
"title": "Strings, harp, oud, and guitar"
}
]
},
{
"title": "Recording"
}
]
},
{
"Dance": [
{
"title": "Choreography"
},
{
"title": "Dance notation"
},
{
"title": "Ethnochoreology"
},
{
"title": "History of dance"
}
]
},
{
"Television": [
{
"title": "Television studies"
}
]
},
{
"Theatre": [
{
"title": "Acting"
},
{
"title": "Directing"
},
{
"title": "Dramaturgy"
},
{
"title": "History"
},
{
"title": "Musical theatre"
},
{
"title": "Playwrighting"
},
{
"title": "Puppetry"
}
]
}
]
}
]
}
] 