Variable mapOperationSub`Const`

mapOperationSub: typeof mapOperationSubStrict = ...

Transform a single operation, similar to mapOperation, but also allowing you to target subTypes. e.g. wrapping a distinct around the all project operations not contained in an aggregate expression (invalid algebra anyway):

mapOperationSub({
  type: Algebra.Types.SLICE,
  input: {
    type: Algebra.Types.PROJECT,
    input: {
      type: Algebra.Types.JOIN,
      input: [{
        type: Algebra.Types.EXPRESSION,
        subType: Algebra.ExpressionTypes.AGGREGATE,
        input: { type: Algebra.Types.PROJECT },
      }, { type: Algebra.Types.BGP }],
    },
  },
}, { [Algebra.Types.PROJECT]: {
  transform: projection => algebraFactory.createDistinct(projection),
}}, { [Algebra.Types.EXPRESSION]: { [Algebra.ExpressionTypes.AGGREGATE]: {
  preVisitor: () => ({ continue: false }),
}}});
const returns = {
  type: Algebra.Types.SLICE,
  input: {
    type: Algebra.Types.DISTINCT,
    input: {
      type: Algebra.Types.PROJECT,
      input: {
        type: Algebra.Types.JOIN,
        input: [{
          type: Algebra.Types.EXPRESSION,
          subType: Algebra.ExpressionTypes.AGGREGATE,
          input: { type: Algebra.Types.PROJECT },
        }, { type: Algebra.Types.BGP }],
      },
    },
  },
};

Param: startObject

the object from which we will start the transformation, potentially visiting and transforming its descendants along the way.

Param: nodeCallBacks

a dictionary mapping the various operation types to objects optionally containing preVisitor and transformer. The preVisitor allows you to provide TransformContext for the current object, altering how it will be transformed. The transformer allows you to manipulate the copy of the current object, and expects you to return the value that should take the current objects place.

Param: nodeSpecificCallBacks

Same as nodeCallBacks but using an additional level of indirection to indicate the subType.

Returns

the result of transforming the requested descendant operations (based on the preVisitor) using a transformer that works its way back up from the descendant to the startObject.