node.js | 易学教程

Cygwin Path Error: Cannot find module 'C:\cygdrive\c\…'

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问题 I am using Cygwin on Windows 7 and it was working as expected until I updated it a couple of days ago. Now when I try to run a makefile for my NodeJs app I get the errors about paths. In error stack I see all the paths have double reference to C drive: C:\cygdrive\c\... Update : Reproduced in Git bash, Windows command line and Cygwin shells. Any ideas how to fix this? 回答1: Make sure the C:\cygdrive\c path is a native, Windows-style symbolic link to just C:\ as that is the expected behavior of

Mongoose join two collections and get only specific fields from the joined collection

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问题 I have a problem joining two collections in mongoose. I have two collections namely: student and exams. Student model: { fullname: { type: String, required: true }, email: { type: String, required: true }, } Exams model: { test: { type: String, required: false }, top10: [ type: { studentId: { type: String, required: true }, score: { type: Number, required: false }, } ] } Now, I want to join them two by studentId . The result should be: { "test": "Sample Test #1", "students": [ { "studentId":

从零入门 Serverless | 函数计算的可观测性

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作者 | 夏莞阿里巴巴函数计算团队本文整理自《Serverless 技术公开课》，关注“Serverless”公众号，回复“入门”，即可获取 Serverless 系列文章 PPT。 **导读：**本文主要分为三个部分：概述中介绍可观测性的基本概念，主要包括 Logging、Metrics、Tracing 三个方面；然后详细介绍函数计算上的 Logging、Metrics、Tracing；最后以几个常见场景为例，介绍在函数计算中如何快速定位问题并解决问题。概述可观测性是什么呢？维基百科中这样说：可观测性是通过外部表现判断系统内部状态的衡量方式。在应用开发中，可观测性帮助我们判断系统内部的健康状况。在系统出现问题时，帮助我们定位问题、排查问题、分析问题；在系统平稳运行时，帮助我们评估风险，预测可能出现的问题。评估风险类似于天气预报，预测到明天下雨，那出门就要带伞。在函数计算的应用开发中，如果观察到函数的并发度持续升高，很可能是业务推广团队的努力工作导致业务规模迅速扩张，为了避免达到并发度限制触发流控，开发者就需要提前提升并发度。可观测性包括三个方面：Logging、Metrics、Tracing Logging 是日志，日志记录了函数运行中的关键信息，这些信息是离散且具体的，结合错误日志与函数代码可以迅速定位问题。 Metrics 是指标，是聚合的数据

Accessing jasmine with testRunner set to jest-circus results in: ReferenceError: jasmine is not defined

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问题 On default jest allows you to simply access jasmine globally. But as soon as you switch the testRunner to jest-circus , jasmine is undefined. Following is a minimal, reproducible example: babel.config.js module.exports = { presets: [["@babel/preset-env", { targets: { node: "current" } }]], }; jasmine.spec.js it("check jasmine", () => { console.log(jasmine); }); jest.config.js module.exports = { rootDir: ".", testRunner: "jest-circus/runner", }; package.json { "name": "test-jest", "version":

Is is possible to represent a firestore Query as string

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问题 It is possible to represent a CollectionReference as a string with the getter proprety path . This is very handy for unit tests. For example admin.firestore().collection('cities').doc('LA').path returns "cities/LA" What about Query represented as String ? For example is there a way to something like this admin.firestore().collection('cities').where('name','==','LA').toString() to print something like this this: "cities/{where $name=='LA'}" This would be handy for unit testing 回答1: From this

how to use nodemailer in nodejs for bulk data sending?

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问题 i have nodemailer code below, its fine and working.My problem is to send individual data to individual email. id_array have two emails and no_array have two individual data, How do i send "1" to prayag@cybrosys.in and "2" to blockchain@cybrosys.net? var id_array = ["prayag@cybrosys.in","blockchain@cybrosys.net"]; var no_array = ["1","2"]; var mailer = require("nodemailer"); // Use Smtp Protocol to send Email var smtpTransport = mailer.createTransport({ service: "Gmail", auth: { user: "mymail

how to use nodemailer in nodejs for bulk data sending?

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how to use nodemailer in nodejs for bulk data sending?

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Unable to mock node-fetch using fetch-mock

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问题 I am trying to do unit testing for a simple function which sends a get request, receives a response and then returns a promise object with the success or the failure message. Following is the function: module.exports.hello = async (event, context) => { return new Promise((resolve, reject) => { fetch("https://httpstat.us/429", { headers: { 'Content-Type': 'application/json' } }).then(response => { console.log(response); if (response.status == 200) { return response; } else { throw Error

Random access in node.js

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问题 Does node.js support writing random access? I see this package, but it doesn't work (if I write two or more parts, the file is corrupt) 回答1: fs core library should suffice for that. Here is the list of functions to use: fs.open(path, flags, [mode], callback) fs.write(fd, buffer, offset, length, position, callback) fs.writeSync(fd, buffer, offset, length, position) fs.read(fd, buffer, offset, length, position, callback) fs.readSync(fd, buffer, offset, length, position) They are analogous to