來源格式與預期記錄
這是原創假設轉換例子。輸入限下列欄位的普通、無循環 JSON 形記錄,統一記錄格式及拒絕代碼由本例訂明。若換來源,先修改格式約定。
來源有 metrics、values、units 三組平行陣列,長度須相同,標籤非空,數值須有限。相同位置合成一份 observation。單位字樣照來源保留,此處不換算;三組都空便產生空清單。
| 個案 | 輸入記錄(JSON) | 預期輸出(JSON) |
|---|---|---|
| 對齊各欄位置 | {"metrics":["mass","length"],"values":[12,0],"units":["kg","mm"]} | {"ok":true,"value":{"observations":[{"metric":"mass","value":12,"unit":"kg"},{"metric":"length","value":0,"unit":"mm"}]}} |
| 拒絕欄長不同 | {"metrics":["mass"],"values":[12],"units":[]} | {"ok":false,"error":"COLUMN_LENGTH"} |
| 保留沒有觀察 | {"metrics":[],"values":[],"units":[]} | {"ok":true,"value":{"observations":[]}} |
在本機執行轉換
把完整例子以 JavaScript 模組在 Node.js 執行,內含純轉換函數、三個輸入及寫明的預期輸出,對不上便由斷言停止。拒絕個案回傳 ok=false 及代碼,不回傳半份統一記錄。
import assert from 'node:assert/strict';
function observationColumns(i){
const fail=error=>({ok:false,error});if(!i||![i.metrics,i.values,i.units].every(Array.isArray))return fail('OBSERVATION_COLUMNS');
if(i.metrics.length!==i.values.length||i.metrics.length!==i.units.length)return fail('COLUMN_LENGTH');
if(i.metrics.some(x=>typeof x!=='string'||!x)||i.units.some(x=>typeof x!=='string'||!x)||i.values.some(x=>typeof x!=='number'||!Number.isFinite(x)))return fail('OBSERVATION_VALUE');
return {ok:true,value:{observations:i.metrics.map((metric,n)=>({metric,value:i.values[n],unit:i.units[n]}))}};
}
// Original synthetic cases; expected outputs are literal records.
const cases = [
{
"label": "Zip corresponding columns",
"input": {
"metrics": [
"mass",
"length"
],
"values": [
12,
0
],
"units": [
"kg",
"mm"
]
},
"expected": {
"ok": true,
"value": {
"observations": [
{
"metric": "mass",
"value": 12,
"unit": "kg"
},
{
"metric": "length",
"value": 0,
"unit": "mm"
}
]
}
}
},
{
"label": "Reject unequal arrays",
"input": {
"metrics": [
"mass"
],
"values": [
12
],
"units": []
},
"expected": {
"ok": false,
"error": "COLUMN_LENGTH"
}
},
{
"label": "Preserve no observations",
"input": {
"metrics": [],
"values": [],
"units": []
},
"expected": {
"ok": true,
"value": {
"observations": []
}
}
}
];
for (const sample of cases) {
const actual = observationColumns(sample.input);
assert.deepEqual(actual, sample.expected);
console.log(sample.label, JSON.stringify(actual));
}
判清邊界個案
欠一個單位,為何不能把下一個單位移前?
查看參考答案
欠格已破壞位置依據,配對前便以 COLUMN_LENGTH 拒絕。完整個案的 length=0、單位 mm 仍是一份零值觀察。