Published
Edited
Aug 1, 2021
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2 stars
lokiVersion = "1.5.12"
loki = require(`lokijs@${lokiVersion}/build/lokijs.min.js`)
LokiIndexedAdapter = require(`lokijs@${lokiVersion}/build/loki-indexed-adapter.min.js`)
db = {
return new Promise((resolve, reject) => {
try {
const db = new loki('experiment.db', {
adapter: new LokiIndexedAdapter(),
autoload: true,
autoloadCallback: () => resolve(db)
});
} catch (error) {
reject(error);
}
});
}
Inputs.button("Delete Database", {
reduce: () =>
db.close(() => {
db.deleteDatabase(() => {
mutable users.clear();
mutable users = users;
});
})
})
mutable users = {
const users = db.getCollection("users");
if (users) return users;
return db.addCollection('users', { indices: ['email'] });
}
Inputs.table(users.data)
Inputs.button("Clear Rows", {
reduce: () => {
users.clear();
db.save();
mutable users = users;
}
})
Inputs.button("Insert Rows", {
reduce: () => {
users.insert({ name: 'odin', email: 'odin@lokijs.org', age: 38 });
users.insert({ name: 'thor', email: 'thor@lokijs.org', age: 25 });
users.insert({ name: 'stan', email: 'stan@lokijs.org', age: 29 });
users.insert({ name: 'oliver', email: 'oliver@lokijs.org', age: 31 });
users.insert({ name: 'hector', email: 'hector@lokijs.org', age: 15 });
users.insert({ name: 'achilles', email: 'achilles@lokijs.org', age: 31 });
db.save();
mutable users = users;
}
})
csvParser = require("papaparse")
chunkSize = 5000
viewof file = html`<input type=file accept=".csv">`
uploadResult = {
return new Promise((resolve, reject) => {
try {
const workings = { chunkCount: 0, errors: [], meta: {}, rowCount: 0 };
csvParser.parse(file, {
chunk: chunk => processChunk(workings, chunk),
chunkSize: chunkSize,
complete: () => resolve(buildSummary(workings)),
header: true,
skipEmptyLines: true
});
} catch (error) {
reject(error);
}
});
}
processChunk = (workings, chunk) => {
workings.chunkCount++;
workings.errors = chunk.errors;
workings.meta = chunk.meta;
workings.rowCount += chunk.data.length;
users.insert(chunk.data);
db.save();
}
buildSummary = workings => {
return {
aborted: workings.meta.aborted,
chunkCount: workings.chunkCount,
chunkSize: chunkSize,
delimiter: workings.meta.delimiter,
errors: workings.errors,
fieldNames: workings.meta.fields,
lastModified: file.lastModified,
lastModifiedDate: file.lastModifiedDate,
linebreak: workings.meta.linebreak,
name: file.name,
rowCount: workings.rowCount,
size: file.size,
type: file.type,
truncated: workings.meta.truncated
};
}
result = users
.chain()
.find({ age: { $gt: 25 } })
.where(function(obj) {
return obj.name.indexOf("in") != -1;
})
.simplesort("age")
.offset(0)
.limit(10)
.data()
Inputs.table(result)
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
