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@Alexgalinier

Alexgalinier/pick.js

Last active Aug 16, 2018
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Deep Pick
const typeOf = _ => Object.prototype.toString.call(_);
// Result can be used with db.collection.find : PARTIALLY
const arrayToSchema = keys =>
keys.reduce((schema, _) => {
if (_.indexOf('.') > -1) {
const [key, rest] = _.split('.');
schema[key] = {
...schema[key],
...arrayToSchema([rest]),
};
} else {
schema[_] = true;
}
return schema;
}, {});
const pick = (obj, schema) =>
Object.keys(schema).reduce((acc, key) => {
switch (typeOf(obj[key])) {
case '[object Object]':
acc[key] = pick(obj[key], schema[key]);
break;
case '[object Array]':
acc[key] = obj[key].map(_ => pick(_, schema[key]));
break;
default:
acc[key] = obj[key];
}
return acc;
}, {});
const obj1 = {
key1: 1,
key2: 2,
key3: 3,
};
const obj2 = {
key1: 1,
key2: 2,
key3: [
{ key5: 5, key6: 6, key7: 7 },
{ key5: 8, key6: 9, key7: 10 },
{ key5: 11, key6: 12, key7: 13 },
],
key4: 4,
};
const obj3 = {
key1: 1,
key2: {
key3: 3,
key4: 4,
key5: 5,
},
};
console.log(pick(obj1, arrayToSchema(['key1', 'key3'])));
console.log(
pick(obj2, arrayToSchema(['key1', 'key3.key5', 'key3.key6', 'key4'])),
);
console.log(pick(obj3, arrayToSchema(['key1', 'key2.key3', 'key2.key4'])));
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