Toolless - File-based Document Database

Field Update Operators

$set

Sets the value of a field:

set.ts

await users.updateOne({ _id: "abc123" }, { $set: { name: "Alice", email: "alice@example.com" } });

Can set nested fields using dot notation:

set-nested.ts

await users.updateOne({ _id: "abc123" }, { $set: { "address.city": "New York" } });

$unset

Removes a field from the document:

unset.ts

await users.updateOne({ _id: "abc123" }, { $unset: { temporaryField: "" } });

The value passed to $unset doesn't matter - the field is removed regardless.

$rename

Renames a field:

rename.ts

await users.updateOne({ _id: "abc123" }, { $rename: { old_name: "new_name" } });

Numeric Operators

$inc

Increments a field by a specified value:

inc.ts

// Increment by 1
await posts.updateOne({ _id: postId }, { $inc: { views: 1 } });

// Decrement by using negative value
await users.updateOne({ _id: "abc123" }, { $inc: { credits: -10 } });

$mul

Multiplies a field by a specified value:

mul.ts

await products.updateOne(
  { _id: productId },
  { $mul: { price: 1.1 } } // 10% increase
);

$min

Updates field only if the specified value is less than current:

min.ts

await stats.updateOne({ _id: "daily" }, { $min: { lowestPrice: 99 } });

$max

Updates field only if the specified value is greater than current:

max.ts

await stats.updateOne({ _id: "daily" }, { $max: { highestPrice: 150 } });

Array Operators

$push

Adds an element to an array:

push.ts

await posts.updateOne(
  { _id: postId },
  { $push: { comments: { text: "Great post!", author: "Bob" } } }
);

Push multiple elements with $each:

push-each.ts

await posts.updateOne(
  { _id: postId },
  { $push: { tags: { $each: ["javascript", "tutorial", "beginner"] } } }
);

$addToSet

Adds element only if it doesn't already exist:

addToSet.ts

await users.updateOne({ _id: "abc123" }, { $addToSet: { roles: "editor" } });

With $each modifier:

addToSet-each.ts

await users.updateOne(
  { _id: "abc123" },
  { $addToSet: { permissions: { $each: ["read", "write", "delete"] } } }
);

$pull

Removes all elements matching a condition:

pull.ts

// Remove specific value
await users.updateOne({ _id: "abc123" }, { $pull: { tags: "deprecated" } });

// Remove matching condition
await users.updateOne({ _id: "abc123" }, { $pull: { scores: { $lt: 50 } } });

$pop

Removes the first or last element of an array:

pop.ts

// Remove last element
await queue.updateOne({ _id: "tasks" }, { $pop: { items: 1 } });

// Remove first element
await queue.updateOne({ _id: "tasks" }, { $pop: { items: -1 } });

Date Operators

$currentDate

Sets field to current date:

currentDate.ts

// Set as Date
await users.updateOne({ _id: "abc123" }, { $currentDate: { lastModified: true } });

// Set as timestamp (milliseconds)
await users.updateOne(
  { _id: "abc123" },
  { $currentDate: { lastModified: { $type: "timestamp" } } }
);

Combining Operators

Multiple operators can be combined in a single update:

combined.ts

await posts.updateOne(
  { _id: postId },
  {
    $set: { title: "Updated Title" },
    $inc: { version: 1, views: 1 },
    $push: { history: { action: "edit", date: new Date().toISOString() } },
    $currentDate: { updatedAt: true },
  }
);

Update with Upsert

Create document if it doesn't exist:

upsert.ts

await users.updateOne(
  { email: "new@example.com" },
  {
    $set: { name: "New User" },
    $setOnInsert: { createdAt: new Date().toISOString() },
  },
  { upsert: true }
);

Always use update operators ($set, $inc, etc.) instead of passing a plain object. A plain object will replace the entire document.

Update Operators

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