How to save an image with custom quality using Jimp?

Im getting this error: leftHalf.quality is not a function

the original image is a jpeg, how to save it with the quality reduced?

            const buffer = Buffer.from(decodedData, 'base64')

            // Read the image using Jimp (synchronously)
            const image = await Jimp.read(buffer)

            // Get image dimensions
            const width  = image.width
            const height = image.height

            // Calculate the split point (vertical split)
            const splitPoint = Math.floor(width / 2)

            // Create two new images
            const leftHalf = image.clone().crop({ x: 0, y: 0, w: splitPoint, h: height })
            const rightHalf = image.clone().crop({ x: splitPoint, y: 0, w: width - splitPoint, h: height })

            await leftHalf.write('leftHalf.jpg')
            await rightHalf.write('rightHalf.jpg')

            await new Promise((resolve, reject) =>
            {
                leftHalf.quality(70).write('leftHalf2.jpg', (err) =>
                    {
                        if (err) reject(err)
                        else resolve()
                    })
            });

await leftHalf.write(‘leftHalf.jpg’)

await rightHalf.write(‘rightHalf.jpg’)

Both saves the images correctly, but how to also save it with the quality reduced to also reduce their sizes?

I have "jimp": "^1.6.0"