---
title: Redis
pagination_prev: demos/desktop/index
pagination_next: demos/local/index
sidebar_custom_props:
  type: nosql
---

Redis has 5 core data types: "String", List", "Set", "Sorted Set", and "Hash".
Since the keys and values are limited to simple strings (and numbers), it is
possible to store complete databases in a single worksheet.

![SheetJSRedis.xlsx](pathname:///nosql/sheetjsredis.png)

## Integration Details

:::note

[`SheetJSRedis.mjs`](pathname:///nosql/SheetJSRedis.mjs) exports the methods:
- `redis_to_ws` creates a SheetJS worksheet by querying a redis client
- `ws_to_redis` creates an array of query objects from the SheetJS worksheet

:::

The first row holds the data type and the second row holds the property name.

The "Exporting Data" snippets generate arrays of arrays that can be added to a
worksheet using `sheet_add_aoa`.  Since the data is column-oriented, the goal is
to add the data starting in the first row of the column after the data:

```js
function add_aoa_to_next_column(worksheet, aoa) {
  /* get range of worksheet */
  const range = XLSX.utils.decode_range(worksheet["!ref"])
  /* the origin to write new data will start in the column after the range */
  const origin = XLSX.utils.encode_cell({
    r: 0, // start on first row
    c: range.e.c + 1 // column after end
  });
  /* add data */
  XLSX.utils.sheet_add_aoa(worksheet, aoa, { origin });
}
```

The "Importing Data" snippets generate redis queries. The `ws_to_redis` function
first generates an array of arrays with `sheet_to_json`:

```js
const aoa = XLSX.utils.sheet_to_json(worksheet, { header: 1 });
```

#### Strings

Strings can be stored in a unified String table. The first column holds keys
and the second column holds values:

```
XXX|    A    |   B   |
---+---------+-------+
 1 | Strings |       |
 2 |         |       |
 3 | Hello   | World |
 4 | Sheet   | JS    |
```

The SheetJS array-of-arrays representation of the string table is an array of
key/value pairs:

```js
const aoa = ["Strings"]; aoa.length = 2; // [ "Strings", empty ]
const keys = await client.KEYS("*");
for(let key of keys) {
  const type = await client.TYPE(key);
  // highlight-start
  if(type == "string") aoa.push([key, await client.GET(key)]);
  // highlight-end
}
```

#### Lists

Lists are unidimensional and can be stored in their own columns.

```
XXX|    C    |
---+---------+
 1 | List    |
 2 | List1   |
 3 | List1V1 |
 4 | List1V2 |
```

The SheetJS array-of-arrays representation of lists is a column of values.
`LRANGE` returns a simple array of values. `sheet_add_aoa` interprets the result
as one row. The code transposes the result with `values.map(v => [v])`.

```js
const values = await client.LRANGE(key, 0, -1);
const aoa = [ ["List"], [key] ].concat(values.map(v => [v]));
```

#### Sets

Sets are unidimensional and can be stored in their own columns.

```
XXX|   D   |
---+-------+
 1 | Set   |
 2 | Set1  |
 3 | Set1A |
 4 | Set1B |
```

The SheetJS array-of-arrays representation of sets is a column of values.
`SMEMBERS` returns a simple array of values. `sheet_add_aoa` interprets result
as one row. The code transposes the result with `values.map(v => [v])`.

```js
const values = await client.SMEMBERS(key);
const aoa = [ ["Set"], [key] ].concat(values.map(v => [v]));
```

#### Sorted Sets

Sorted Sets have an associated score which can be stored in the second column.

```
XXX|    E    | F |
---+---------+---+
 1 | Sorted  |   |
 2 | ZSet1   |   |
 3 | Key1    | 1 |
 4 | Key2    | 2 |
```

The SheetJS array-of-arrays representation is an array of key/score pairs.
`ZRANGE_WITHSCORES` returns an array of objects which can be reshaped.

```js
const values = await client.ZRANGE_WITHSCORES(key, 0, -1);
const aoa = [ ["Sorted"], [key] ].concat(values.map(v => [v.value, v.score]));
```

#### Hashes

Hashes are stored like the string table, with key and value columns in order.

```
XXX|   G   |   H   |
---+-------+-------+
 1 | Hash  |       |
 2 | Hash1 |       |
 3 | Key1  | Val1  |
 4 | Key2  | Val2  |
```

The SheetJS array-of-arrays representation is an array of key/value pairs.
`HGETALL` returns a plain object which can be converted using `Object.entries`:

```js
const values = await client.HGETALL(key);
const aoa = [ ["Hash"], [key] ].concat(Object.entries(values));
```

## Complete Example

:::note

This demo was last tested on 2023 February 23 with Redis 7.0.8, Redis connector
module 4.6.4 and NodeJS 18.14.2.

:::

:::warning

The most recent version of the `redis` node module does not work with most
versions of NodeJS. It is "ESM-only", requiring NodeJS 18 or later. As a result,
this demo also requires NodeJS version 18.

Questions regarding the `redis` library and the decision to drop traditional
NodeJS "CommonJS" module support should be directed to the Redis team.

:::

0) Set up and start a local Redis server.  On Intel macOS:

```bash
brew install redis@7.0.8
```

1) Download the following scripts:

- [`SheetJSRedis.mjs`](pathname:///nosql/SheetJSRedis.mjs)
- [`SheetJSRedisTest.mjs`](pathname:///nosql/SheetJSRedisTest.mjs)

```bash
curl -LO https://docs.sheetjs.com/nosql/SheetJSRedis.mjs
curl -LO https://docs.sheetjs.com/nosql/SheetJSRedisTest.mjs
```

2) Install dependencies and run:

```bash
npm i --save https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz redis@4.6.4
node SheetJSRedisTest.mjs
```

Inspect the output and compare with the data in `SheetJSRedisTest.mjs`.

Open `SheetJSRedis.xlsx` and verify the columns have the correct data