FormatException: Invalid double Regular

[Kahoulam]

Steps to reproduce

1. Create a new project
2. Add tokens.json file
3. Execute the command dart run build_runner build

Expected results

Correctly generate tokens.dart file

Actual results

An error occurred:

FormatException: Invalid double Regular

Version

design_tokens_builder: ^0.2.0+1

Code sample

tokens.json

{
  "global": {
    "fontWeights": {
      "roboto-0": {
        "value": "Regular",
        "type": "fontWeights"
      },
      "roboto-1": {
        "value": "Medium",
        "type": "fontWeights"
      },
      "roboto-2": {
        "value": "SemiBold",
        "type": "fontWeights"
      }
    }
  },
  "$themes": [],
  "$metadata": {
    "tokenSetOrder": [
      "global"
    ]
  }
}

Logs

Console logs

[INFO] Generating build script completed, took 232ms
[INFO] Reading cached asset graph completed, took 64ms
[INFO] Checking for updates since last build completed, took 846ms
[WARNING] design_tokens_builder|lib/design_tokens_builder.dart was not found in the asset graph, incremental builds will not work.
 This probably means you don't have your dependencies specified fully in your pubspec.yaml.
[WARNING] Invalidating asset graph due to build script update!
[INFO] Cleaning up outputs from previous builds. completed, took 1ms
[INFO] Generating build script completed, took 41ms
[WARNING] Invalidated precompiled build script due to missing asset graph.
[INFO] Precompiling build script... completed, took 600ms
[WARNING] design_tokens_builder|lib/design_tokens_builder.dart was not found in the asset graph, incremental builds will not work.
 This probably means you don't have your dependencies specified fully in your pubspec.yaml.
[INFO] Building new asset graph completed, took 901ms
[INFO] Checking for unexpected pre-existing outputs. completed, took 0ms
[SEVERE] design_tokens_builder on lib/$lib$:

FormatException: Invalid double
Regular
[INFO] Running build completed, took 36ms
[INFO] Caching finalized dependency graph completed, took 41ms
[SEVERE] Failed after 83ms

Flutter Doctor output

Doctor output

  [✓] Flutter (Channel stable, 3.13.9, on macOS 14.0 23A344 darwin-arm64, locale en-TW)
  [✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
  [✓] Xcode - develop for iOS and macOS (Xcode 15.0.1)
  [✓] Chrome - develop for the web
  [✓] Android Studio (version 2022.3)
  [✓] VS Code (version 1.84.0)
  [✓] Connected device (1 available)
  [✓] Network resources