This guide will describe how we can use a range of different operators within our transformations to change the context of the data which we are transforming. The default context is within the payload data, but this can be changed instead to data created previously in the transformation.<\/p>\n\n\n\n
Note that a sample payload has been included here<\/a> at the bottom of the page for you to use in exploring the transformations included here.<\/p>\n\n\n\n Throughout the guides and tutorials on this site, you may see references to the This results in:<\/p>\n\n\n\n We can also use the current node operator to evaluate our data. In our sample data, The following more complex transformation shows an example of the current node being referred to a number of times to produce a result. In this case, the result is essentially the same as in the first example but includes the addition of an index key onto each object within Note the use of the pipe expression on the first line. You can find an explanation of this here<\/a>. The current node is used in four different instances:<\/p>\n\n\n\nCurrent Node – @<\/h2>\n\n\n\n
@<\/code><\/strong> symbol. This is defined by JMESPath as the ‘current node’<\/a>. The current node is the point in the payload that our transformation is currently referring to. To illustrate this, consider the sample data at the end of this guide. Here we can use the current node to assign the entire payload to a single data point:<\/p>\n\n\n\n{\n \"Data\": @\n}<\/code><\/pre>\n\n\n\n{\n \"Data\": {\n \"Globals\": {\n\t...\n },\n \"SalesData\": [\n {\n \"Date\": \"4\/1\/21\",\n \"Region\": \"Denmark\",\n \"SalesRep\": \"S. Ehlers\",\n \"Product\": \"Template\",\n \"Units\": \"99\",\n \"PricePerUnit\": \"52.99\",\n \"TotalCost\": \"5246.01\"\n },\n\t...\n ]\n }\n}<\/code><\/pre>\n\n\n\nEvaluating data using the current node<\/h2>\n\n\n\n
SalesData<\/code> is an array of 11 different objects, each of which includes a TotalCost <\/code>value. The following simple transformation allows us to create a single object to contain both our minimum and maximum values. As SalesData<\/code> has been defined in the first line as the context for the object, we can simply use the current node operator to refer to this.<\/p>\n\n\n\n{\n min_max: SalesData.{\n max: max_by(@, &TotalCost),\n min: min_by(@, &TotalCost)\n }\n}<\/code><\/pre>\n\n\n\nSalesData<\/code> to allow for a unique identifier to be added. <\/p>\n\n\n\n{\n data: sort_by(SalesData[*] | map(&merge(@,{__index: __index}), @), &TotalCost).{\n min: @[0],\n max: @[-1]\n }\n}<\/code><\/pre>\n\n\n\nTotalCost <\/code>then select the first and last objects.<\/li><\/ul>\n\n\n\nThe $ operator<\/h2>\n\n\n\n