fflate/docs/interfaces/asyncgzipoptions.md

Interface: AsyncGzipOptions

Options for compressing data asynchronously into a GZIP format

Hierarchy

• GzipOptions

• AsyncOptions

↳ AsyncGzipOptions

Index

Properties

• consume
• filename
• level
• mem
• mtime

Properties

consume

• Optional consume: boolean

Inherited from AsyncDeflateOptions.consume

Whether or not to "consume" the source data. This will make the typed array/buffer you pass in unusable but will increase performance and reduce memory usage.

---

filename

• Optional filename: string

Inherited from GzipOptions.filename

The filename of the data. If the gunzip command is used to decompress the data, it will output a file with this name instead of the name of the compressed file.

---

level

• Optional level: 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

Inherited from DeflateOptions.level

The level of compression to use, ranging from 0-9.

0 will store the data without compression. 1 is fastest but compresses the worst, 9 is slowest but compresses the best. The default level is 6.

Typically, binary data benefits much more from higher values than text data. In both cases, higher values usually take disproportionately longer than the reduction in final size that results.

For example, a 1 MB text file could:

• become 1.01 MB with level 0 in 1ms
• become 400 kB with level 1 in 10ms
• become 320 kB with level 9 in 100ms

---

mem

• Optional mem: 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12

Inherited from DeflateOptions.mem

The memory level to use, ranging from 0-12. Increasing this increases speed and compression ratio at the cost of memory.

Note that this is exponential: while level 0 uses 4 kB, level 4 uses 64 kB, level 8 uses 1 MB, and level 12 uses 16 MB. It is recommended not to lower the value below 4, since that tends to hurt performance. In addition, values above 8 tend to help very little on most data and can even hurt performance.

The default value is automatically determined based on the size of the input data.

---

mtime

• Optional mtime: Date | string | number

Inherited from GzipOptions.mtime

When the file was last modified. Defaults to the current time. If you're using GZIP, set this to 0 to avoid revealing a modification date entirely.