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cesanta
v7
C2015–2023
cesanta / v7

v7

Embedded JavaScript engine for C/C++

Web DevelopmentHardware & Embedded
Explore on GitHubRead Hacker News discussions
6Distinct people
10Mentions
0Explicit recommenders
1.5KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Embedded JavaScript engine for C/C++

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year10 dated mentions

Observed mentions: 2015-07-25 21:19:53 UTC to 2023-07-02 12:20:18 UTC.

01232015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments20152016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments2017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments20192020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2023

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC202
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC312
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC101
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC101
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC000
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC000
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC101
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC101
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC101

What Hacker News says

10 sources
hootbootscoot·Jun 29, 2021
1) I did not originate this "is trash" phrase, but replied to a parent comment you had rather excoriate. I said that Javascript is fine for what it was designed for: a single threaded UI event loop in a web browser. It is NOT good as a high-volume web server, for example. Http has a request and response cycle and is deliberately stateless such that all data goes out of scope and the entire thing can be deconstructed and, poof, no memory overhead nor leaks. It was designed that way, as a protocol. 2) I saw your comment below. You cannot write device drivers in the language of your choice on any of todays popular operating systems, nor on any embedded devices. Device drivers must have low level access to things like memory locations and cpu registers. Such things are not exposed to Javascript and not available. This is not even speaking abo
Read the rest
ut performance and garbage collection etc. Look, Javascript is someones computer program. It can be implemented in very little code: here's an example: https://github.com/cesanta/v7 Languages are not all equal nor do they all function in the same way, and that's not my opinion. Javascript syntax itself is one thing, and you can certainly feel free to Javascriptify some C++ libraries and make it all look a certain way for specific tasks, while managing things behind the scenes, up to a point... but there is no getting around the fact that SOMEONE and some languages are needed to implement low level systems functionality. the power of Cython or the Python C FFI is that it allows you to script/glue modular native code. You then state "C++14 may have been ratified 7 years ago but it's not the target code your build chain spits out" no, a C++ COMPILER spits out assembler code that then gets assembled and linked into an executable. The C++ or C code corresponds directly to a given set of assembler instructions which correspond directly to CPU instructions. You claim that Python programming of microcontrollers is mainstream, but this is not true nor possible. Python SCRIPTING of code modules (that cannot be written in Python) is certainly one way to assemble a system from pre-built legos. If you refer to knowing what I'm talking about as gatekeeping and egoism, might I suggest that you insist less forcefully in the correctness of incorrect things you state? we could be done with this spat in short order if YOU would refrain from speaking falsehoods. lies.untrue things. I look forward to your lisp c compiler. make sure that it's 100% lisp from the bottom up, or I'll consider you're having ceded my point. Consider that the lisp you author in has a garbage collection system that lisp cannot have written originally, nor has any semantics for the underlying memory structures of, but hey, I guess if one is committed to pretending that all languages are equal for all tasks, who am I to question ones self-identification with a given language.
In JavaScript Is Weird
oso2k·Jan 25, 2017
Is this a re-packaged v7 [0] (it's from Cesanta as well)? mjs.c is 477K. It looks like it as v7.c is 475K [1]. It shaves whole entire 1MB from my staticly linked builds (v7 1.9MB vs. mjs 998K), and almost 2MB from dynamically linked builds (v7 1.9MB vs. mjs 99K) on amd64. If it shares the same underlying architecture and api [2] then this is a pretty great achievement. In their docs, they claim 25K storage and 10K RAM. Blog post claims 25K storage and 1K RAM. [0] https://github.com/cesanta/mjs/blob/master/mjs.c [1] https://github.com/cesanta/v7/blob/master/v7.c [2] https://docs.cesanta.com/v7/master/#/v7-internals/
In mJS – A new approach to embedded scripting
ithkuil·Mar 1, 2016
Smart.js is based on two projects: - V7: a small portable JS VM (https://github.com/cesanta/v7) - mongoose: a portable async multiprotocol networking library (https://github.com/cesanta/mongoose) Both of those projects are independent and have some traction on their own; but you're right that we should make it more explicit. Mongoose is out there since 2004 and is a quite popular embedded http server. We added many other protocols to it, including also COAP and DNS. Arduino libs are not used because they are not async and not portable. Honestly I don't know about node-red, sounds interesting; however node's V8 VM is too heavyweight for the smallest devices we aim to support. Smart.js does expose a nodejs-compatible core API wherever possible, so it might be possible to port node-red to it.
In From the Trenches: Making an IoT Platform Work with ESP8266 and CC3200

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