TypeScript中Generator用Spread语法在VS Code运行异常问题

The discrepancy between VS Code's Code Runner and ts-node in cmd boils down to how TypeScript is being compiled/executed in each environment, specifically around ES version targeting and iterable handling.

Root Cause #

When you run your code in VS Code's Code Runner, it’s likely using the default TypeScript compiler (tsc) with an ES5 target. Here’s why that breaks things:

• ES5 doesn’t natively support generators or the spread operator on iterables. TypeScript transpiles [...iterable] to Array.prototype.slice.call(iterable) for ES5.
• Generator objects are not array-like (they lack a length property and indexed elements), so calling slice on them throws the TypeError: chain(...).slice is not a function error.

In contrast, ts-node defaults to targeting ESNext/ES2015+, which preserves the spread operator and natively supports generators as iterables. This is why it works correctly in cmd.

Fix 1: Update Your TypeScript Configuration #

Ensure your tsconfig.json targets an ES version that supports generators and iterable spread:

1. Create or edit your tsconfig.json file in the project root:

   {
     "compilerOptions": {
       "target": "ES2015", // Or "ESNext" for latest features
       "module": "CommonJS",
       "strict": true,
       "esModuleInterop": true
     }
   }
   

2. Save the file. Code Runner will now use this configuration to compile TypeScript correctly.

Fix 2: Configure Code Runner to Use ts-node #

Instead of relying on tsc + Node.js, make Code Runner execute TypeScript directly with ts-node (matching your cmd setup):

1. Open VS Code settings (Ctrl+, or Cmd+).
2. Search for Code Runner: Executor Map.
3. Edit the TypeScript entry to use ts-node:

   "code-runner.executorMap": {
     "typescript": "ts-node"
   }
   

   • If ts-node is installed locally (not globally), use npx ts-node instead.
4. Save the settings. Now Code Runner will run your TypeScript code exactly like ts-node does in cmd.

Verification #

After applying either fix, running your code in VS Code should produce the same output as cmd:

[ 'A', 'B', 'C', 'D' ]

Content of the question来源于stack exchange，提问作者Gilad Noy