ItemsPath
The ItemsPath field is used in a Map state to select an array
in the input. A Map state is used to iterate steps for each item in an array
contained in the input. By default, a Map state sets ItemsPath to
"$" selecting the entire input. If the input to the Map state is a
JSON array it will run an iteration for each item in the array, passing that item
to the
iteration as input. For an example of this, see the Map State Tutorial.
The ItemsPath field allows you to specify a location in the input to find the
JSON array to use for iterations. The value of ItemsPath must be a Reference Path, and it must identify
a value that is a JSON array. For instance, consider input to a Map state that
includes two arrays, like the following example.
{
"ThingsPiratesSay": [
{
"say": "Avast!"
},
{
"say": "Yar!"
},
{
"say": "Walk the Plank!"
}
],
"ThingsGiantsSay": [
{
"say": "Fee!"
},
{
"say": "Fi!"
},
{
"say": "Fo!"
},
{
"say": "Fum!"
}
]
}In this case, you could specify which array to use for Map state iterations
by selecting a specific array with ItemsPath. The following state machine
definition specifies the "ThingsPiratesSay" array in the input using
ItemsPath, and will run an iteration of the SayWord pass state for
each item in the "ThingsPiratesSay" array.
{
"StartAt": "PiratesSay",
"States": {
"PiratesSay": {
"Type": "Map",
"ItemsPath": "$.ThingsPiratesSay",
"Iterator": {
"StartAt": "SayWord",
"States": {
"SayWord": {
"Type": "Pass",
"End": true
}
}
},
"End": true
}
}
} When processing input, ItemsPath is applied after InputPath. It operates on the effective
input to the state, after InputPath has filtered the input.
For more information on Map states, see the following:
