Protobuf: 64 bit integer

[sm2017]

According to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER

The Number.MAX_SAFE_INTEGER constant represents the maximum safe integer in JavaScript (2^53 - 1).

The MAX_SAFE_INTEGER constant has a value of 9007199254740991 (9,007,199,254,740,991 or ~9 quadrillion). The reasoning behind that number is that JavaScript uses double-precision floating-point format numbers as specified in IEEE 754 and can only safely represent numbers between -(2^53 - 1) and 253 - 1.

So we have problem with 64 bit integers , When I want to open a uint64 field that is larger than (2^53 - 1) it is rounded to another number

unofficial protobuffer library , https://github.com/dcodeIO/ProtoBuf.js/ , uses https://github.com/dcodeIO/long.js and solved problem

Please use long.js for 64 bit integer

As of ECMA-262 5th Edition, "all the positive and negative integers whose magnitude is no greater than 2^53 are representable in the Number type", which is "representing the doubleprecision 64-bit format IEEE 754 values as specified in the IEEE Standard for Binary Floating-Point Arithmetic". The maximum safe integer in JavaScript is 2^53-1.

Example: 2^64-1 is 18446744073709551615 but in JavaScript it evaluates to 18446744073709552000.

Furthermore, bitwise operators in JavaScript "deal only with integers in the range −2^31 through 2^31−1, inclusive, or in the range 0 through 2^32−1, inclusive. These operators accept any value of the Number type but first convert each such value to one of 2^32 integer values."

In some use cases, however, it is required to be able to reliably work with and perform bitwise operations on the full 64 bits. This is where long.js comes into play.

[amelhaoui]

it has been fixed in 3.4 : https://github.com/google/protobuf/releases
message dummy { uint64 bigInt = 1; [jstype = JS_STRING] }

[SimenB]

Any chance of using BigInt?

[jasonxia23]

Any chance of using BigInt?

Anyone on this?

[shawncao]

I understand adding [jstype = JS_STRING] is an option, however I concern about the performance when I pass millions of bigint through the field repeated int64 big_values. With this option, I guess we pay unnecessary serde of these values

• client: it has to convert long[] to string[] to call the REST API (node.js)
• server: it can get int64_t[] due to the proto declaration, but I guess protobuf pays cost to deserialize strings to int64

So the ideal case is, if protobuf can support bigint (long.js or native bigint if supported), then we can completely remove above conversions, and we don't pay the cost any more.

It will be great if this support can be added.

[juliettepretot]

it has been fixed in 3.4 : https://github.com/google/protobuf/releases
message dummy { uint64 bigInt = 1; [jstype = JS_STRING] }

I wouldn't personally consider this to be a fix. Imho the default unsafe conversion of 64 bit integers to JavaScript numbers is a problem. Merely giving developers the option to overwrite this (on an individual field basis) doesn't justify the unsafe default behavior of silently loosing precision. It is also inconsistent with protobuf's JSON mapping which converts these to strings.

[bennyscetbun]

We just get bitten by the same issue. Silently not converting a uint64 to its full precision is a real issue. Our server is in Golang and using 64bits integer is a basic thing. I understand the JS limitation but maybe we should consider using an open source uint64 library until it s part of the language (if it ever will)
Someone has suggested BigInt.
If you dont want to make BigInt the default for retro compatibility reason. Would you consider adding a new [jstype = JS_BIGINT ?