Skip to main content

Graphile Config Preset

A preset bundles together a list of plugins, and options for various of the "scopes". You may use more than one preset at a time, and presets may also compose (extend) other presets. When a library is passed a list of presets it results in a resolved preset (a preset that has no "extends") using the ResolvePresets algorithm; broadly all the extends are resolved in order, the plugins specified are merged as a set (each plugin will only be included once) and the options are merged via object merging such that the options specified last win.

NOTE: if you compose two presets (PresetA and PresetB) that both extends the same underlying preset (BASE) and apply some overrides, then the overrides in PresetA will be overridden by re-applying the BASE preset again. For this reason, presets that are expected to be combined with other presets should not extends common/shared presets, instead the end-user should be expected to add these presets themselves.

NOTE: the order of presets is significant.


  1. Let {finalPreset} be an empty preset.
  2. For each {preset} in {presets}:
    1. Let {resolvedPreset} be {ResolvePreset(preset)}.
    2. Let {finalPreset} be {MergePreset(finalPreset, resolvedPreset)}.
  3. Return {finalPreset}.


  1. Let {presets} be the list specified in the {extends} property of {preset} (or an empty list if none specified).
  2. Let {basePreset} be {ResolvePresets(presets)}.
  3. Return {MergePreset(basePreset, preset)}.

MergePreset(basePreset, extendingPreset):

  1. Let {finalPreset} be an empty preset.
  2. Assert: {basePreset} has an empty or non-existent {extends} property.
  3. Let {plugins} be the list of plugins defined in {basePreset} union the list of plugins in {extendingPreset}.
  4. Let the list of plugins for {finalPreset} be {plugins}.
  5. Let {scopes} be the list of scopes defined in {basePreset} union the list of scopes in {extendingPreset}.
  6. For each {scope} in {scopes}:
    1. Let {baseScope} be the {scope} in {basePreset}.
    2. Let {extendingScope} be the {scope} in {extendingPreset}.
    3. If {baseScope} and {extendingScope} both exist:
      1. Let {scope} in {finalPreset} be the result of merging {baseScope} and {extendingScope} akin to Object.assign({}, baseScope, extendingScope).
    4. Else: let {scope} in {finalPreset} be whichever of {baseScope} and {extendingScope} actually exist.
  7. Return {finalPreset}.

IMPORTANT: the default name must not be used as a top-level key in a preset to enable compatibility with the various ESM emulations.