Support a number as key in object when packing as MAP? #187
Comments
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You can already use an Array as the data source of |
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Thanks for the reply, I will try this method. |
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I think this is important for interoperability, especially with Python, where integer keys are very common in maps. To support I would perhaps have three: one that uses plain objects, one that uses Map, and one that calls a function asking whether to use a plain object or a Map when serializing/deserializing. |
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I have the same issue. Would be fine if we could annotate fields in some TS interface and then it translated automatically into an object with such interface. |
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same question. Object will automatically convert keys into string type, and Map objects are not supported. How to solve? object or Map need to encode: |
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This is extremely important when encoding sparse arrays with very large indices, e.g. |
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I use this code to approach this issue, by creating custom encoder var Hex = "816501"; // {101: 1}
var MsgPackEncoder = require("@msgpack/msgpack").Encoder
var MsgPack_encoderWithNumberMap = (value, options) => {
const encoder = new MsgPackEncoder(options);
encoder.encodeMap = (object, depth) => {
const keys = Object.keys(object);
if (encoder.sortKeys) {
keys.sort();
}
const size = encoder.ignoreUndefined ? encoder.countWithoutUndefined(object, keys) : keys.length;
if (size < 16) {
// fixmap
encoder.writeU8(0x80 + size);
}
else if (size < 0x10000) {
// map 16
encoder.writeU8(0xde);
encoder.writeU16(size);
}
else if (size < 0x100000000) {
// map 32
encoder.writeU8(0xdf);
encoder.writeU32(size);
}
else {
throw new Error(`Too large map object: ${size}`);
}
for (const key of keys) {
const value = object[key];
if (!(encoder.ignoreUndefined && value === undefined)) {
// Check if Key String is a number
if(Number(key) == key) {
encoder.encodeNumber(Number(key));
} else {
encoder.encodeString(key);
}
encoder.doEncode(value, depth + 1);
}
}
}
return encoder.encodeSharedRef(value);
}
var B1 = msgPack.decode(Buffer.from(Hex, "hex"))
var B2 = MsgPack_encoderWithNumberMap(B1, {})
var B3 = msgPack.encode(B1, {})
console.log(Buffer.from(B2).toString("hex") == Hex) // true - 816501
console.log(Buffer.from(B3).toString("hex") == Hex) // false - 81a331303101 |
Hi,
I am developing a protocol in a resource constrain platform and suffer from very limited bandwidth.
We are using map(integer: any) to transfer messages.
However, this lib only packs objects as map() while the "key" in the object is required to be a string.
Using string adds at least additional 2 bytes compared to the integer, while the map(integer: bool or integer) can be only 3 bytes.
I understand this request is not commonly used in the web dev, but it is very useful for us to reduce the bandwidth.
Thanks,
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