code: function createInjection(fileId, categoryPrefix, declaration, idx, declarationResultHandler) {
    const fnName = `${FN_PREFIX}_${fileId}_${categoryPrefix}_${declaration.declarationClean}_${idx}`;
  
    const injectedFunction = function(sassValue) {
      const value = createStructuredValue(sassValue);
      declarationResultHandler(declaration, value, sassValue);
      return sassValue;
    };
  
    let injectedCode = `@if global_variable_exists('${declaration.declarationClean}') { 
      $${fnName}: ${fnName}(${declaration.declaration}); 
    }\n`
  
    return { fnName, injectedFunction, injectedCode };
  }
docs: Create injection function and source for a file, category, declaration and result handler