VSCode build not working - No build task defined. Mark a task with 'isBuildCommand' in the tasks.json file

Question

I have fresh install of VSCode, and this tiny basic TypeScript app.

First time, when I want to build the app, VScode needs to generate tasks.json.

And it worked long time ago before.

Today I am getting this weird message

No build task defined. Mark a task with 'isBuildCommand' in the tasks.json file.

I don't remember seeing this message before.

But, OK, I click Configure Build Task, select TypeScript task, and tasks.json gets generated.

But, what happens, after I try to build now, Ctrl+Shift+B, and I get the exact same message again

Any ideas? Thanks.

BTW, adding this setting to tasks.json doesnt solve the problem.

Answer 1

This issue was also adressed here: https://github.com/Microsoft/vscode/issues/24796

It says:

Closing and reopening the window (without starting Code) resolves this issue.

Answer 2

Closing and reopening the window

Which window? Closing and reopening the tasks.json window didn't work for me (in VS Code 1.11.2).

Here's what did though:

• Closing and re-opening Visual Studio Code
• Ctrl-Shift-B (or your build shortcut)

Answer 3

In my case, my tasks.json had some nonsense in it. Instead of the "command" property, I wrongly named it "executable"...*

So consider if:

1. Your JSON is valid syntactically (see screenshot below)
2. Your JSON is valid according to what VS Code expects

Syntactically invalid:

Schematically invalid:

And while I think the other answers are probably correct (I can't reproduce so I can't verify; the issue has been fixed...), I think when the comment said ...

Closing and reopening the window (without starting Code)

... it may have meant the Reload Window command.

---

*I wrongly named the tasks.json property "executable", vs "command" because...

1. I thought "command" was causing issues (it wasn't)
2. I wanted to run a specific executable in a specific directory like "C:/somewhere/python.exe"; ("command" can do that).

I don't know why I thought "executable" was valid! I thought I was referencing some example, but can't find it... :) )

Answer 4

[As of 18th September 2021] and VS Code version: 1.60.0

For me, it turned out to be that I wasn't having "isBuildCommand": true.

I understand that this post already assumes that isBuildCommand is already included. But VS Code didn't include this by default for me and being new to VS code if I reached this page, it might be helpful to someone else who is new.

I wanted to have two configurations - Debug and Release. This is how my two configs looks -

{
    "label": "build Debug",
    "command": "dotnet",
    "type": "process",
    "isBuildCommand": true,
    "args": [
        "build",
        "${workspaceFolder}/ABCD/ABCD.csproj",
        "/property:GenerateFullPaths=true",
        "/consoleloggerparameters:NoSummary"
    ],
    "problemMatcher": "$msCompile"
},
{
    "label": "build Release",
    "command": "dotnet",
    "type": "process",
    "isBuildCommand": true,
    "args": [
        "build",
        "${workspaceFolder}/ABCD/ABCD.csproj",
        "/property:GenerateFullPaths=true",
        "/consoleloggerparameters:NoSummary",
        "-c",
        "Release"
    ],
    "problemMatcher": "$msCompile"
}