Linq2Fire

Supports special operators: IN, NOT IN, OR, !=, startsWith (^=), array-contains (has) and many more

``js
import linq from "linq2fire";
const db = firebase.firestore();

const printDocs = heading => docs => {
console.log("", heading.toUpperCase(), "");
docs.forEach(doc => console.log(doc.id, doc.data()));
console.log();
};

const test = async () => {
const $todos = linq(db).from("todos");

await $todos
.orderBy({ text: "desc" })
.orderBy({ text: "desc" })
.where({ category: "A" })
.get()
.then(printDocs("Duplicate order by"));

await $todos.remove();

// add single doc
await $todos.set(1, {
text: "Task 1"
});
// add multiple docs
await $todos.set({
1: {
text: "Task 1",
category: "A"
},
2: {
text: "Task 2",
category: "B",
categories: ["A", "B"]
},
3: {
text: "Task 3",
categories: ["A"]
},
4: {
text: "Task 4",
category: "B",
categories: ["B"]
},
5: {
text: "Task 5",
category: "A"
},
6: {
text: "Other task",
category: "C"
}
});

await $todos
.where({
// not in operator
"text<>": ["Task 1", "Task 2"]
})
.get()
.then(printDocs("Find tasks which is not in [1, 2]"));

await $todos
.where({
"text ^=": "Task"
})
.get()
.then(printDocs("Find all tasks which starts with Task"));

await $todos
.orderBy({ text: "desc" })
.first()
.then(first => {
console.log("Get first task ", first && first.data());
});

await $todos
.where({
// in operator
text: ["Task 1", "Task 2"]
})
.get()
.then(printDocs("Find tasks: 1, 2, 3"));

await $todos
.where({
"text <": "Task 2"
})
.get()
.then(printDocs("Find all tasks which has text less than Task 2"));

await $todos
.where({
// not equal
"text <>": "Task 1"
})
.get()
.then(printDocs("Find all tasks which has text not equal Task 1"));

await $todos
.where({
// find by id
"@id": 1
})
.get()
.then(printDocs("Find task by id"));

await $todos
.where({
// multiple IN operators
text: ["Task 1", "Task 2", "Task 3"],
category: ["A", "B"]
})
.get()
.then(printDocs("Find task with multiple IN operators"));

await $todos
.where({
text: ["Task 1", "Task 2", "Task 3"],
or: [{ category: "A" }, { category: "B" }]
})
.get()
.then(printDocs("Find task with OR operator "));

// await $todos
// .where({
// 'category array_contains': 'A'
// })
// .get()
// .then(printDocs('Finding task using array_contains operator'));

// get task names
await $todos
.select({ text: "name" })
.get()
.then(console.log);

// join all items using pipe
await $todos
.select(true, "text")
.pipe(String)
.get()
.then(console.log);

// convert task names to uppercase
await $todos
.select(true, "text")
.map("toUpperCase")
.get()
.then(console.log);

await $todos
.select(true, "text")
.map(x => x.toUpperCase())
.get()
.then(console.log);

await $todos
.select(true, "text")
.get()
.then(console.log);

await $todos
.where({
or: {
category: "A",
text: "Task 3"
}
})
.get()
.then(printDocs("Find task with OR operator "));

await $todos
.where({
"categories has": "A"
})
.get()
.then(printDocs("Find task using has operator"));

await $todos
.where({
"categories array-contains": "A"
})
.get()
.then(printDocs("Find task using array-contains operator"));

// support pagination
const pagination = $todos
.limit(1)
.orderBy({
text: "asc"
})
.where({
"text <>": "Task 1"
});

await pagination
.get()
.then(printDocs("Find all tasks which has text not equal Task 1. Page 1"));

await pagination
.next()
.then(printDocs("Find all tasks which has text not equal Task 1. Page 2"));
await pagination
.next()
.then(printDocs("Find all tasks which has text not equal Task 1. Page 3"));
};

test();
``

References:

$3

Create a linq object to wrap db

$3

Create a linq object to wrap collection

$3

Create a linq object to wrap collection, then pass it to callback. This method is useful for chaining calls

$3

Create a linq object to wrap collection

$3

Projects each item of a result set into a new object with specific fields.

$3

Projects each item of a result set into a new object with specific fields.

$3

Transform result set into a array of field value

$3

Projects each item of a result set by using custom selector.

$3

Limit result set

$3

Filter result set by multiple conditions { text: 'abc', 'age >': 100, fieldValueMustBeIn: [1, 2, 3, 4, 5], 'field <>': 0 }
Support operators: >, <, >=, <=, =, ==, ===, <>, !=, !==, has, array-contains.
'has' is shorthand of 'array-contains'

$3

Sort result set by specified fields { field1: 'asc', field2: 'desc' }

$3

Get all documents which is satisfied query condition

$3

Get next result set which starts after last result set

$3

$3

$3

Remove all documents which is satisfied query condition