updated to function and tasks, updated AND operator, resolves #170

CONTRIBUTING.md

@@ -293,7 +293,7 @@ The shortcode structure is the same as above, but the shortcode names are differ
 data = from(bucket: "telegraf/autogen")
   |> range(start: -15m)
   |> filter(fn: (r) =>
-    r._measurement == "mem" AND
+    r._measurement == "mem" and
     r._field == "used_percent"
   )
 ```

content/v2.0/example.md

@@ -33,7 +33,7 @@ This is a paragraph. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nu
 data = from(bucket: "telegraf/autogen")
   |> range(start: -15m)
   |> filter(fn: (r) =>
-    r._measurement == "mem" AND
+    r._measurement == "mem" and
     r._field == "used_percent"
   )
 ```
@@ -442,7 +442,7 @@ This is a paragraph. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nu
 data = from(bucket: "telegraf/autogen")
   |> range(start: -15m)
   |> filter(fn: (r) =>
-    r._measurement == "mem" AND
+    r._measurement == "mem" and
     r._field == "used_percent"
   )
 ```

content/v2.0/process-data/write-a-task.md

@@ -62,7 +62,7 @@ the required time range and any relevant filters.
 data = from(bucket: "telegraf/default")
   |> range(start: -task.every)
   |> filter(fn: (r) =>
-    r._measurement == "mem" AND
+    r._measurement == "mem" and
     r.host == "myHost"
   )
 ```
@@ -111,7 +111,10 @@ to send the transformed data to another bucket:
 ```
 
 {{% note %}}
-You cannot write to the same bucket you are reading from.
+#### Important notes
+- You cannot write to the same bucket you are reading from.
+- In order to write data into InfluxDB, you must have `_time`, `_measurement`,
+  `_field`, and `_value` columns.
 {{% /note %}}
 
 ## Full example task script
@@ -132,7 +135,7 @@ option task = {
 data = from(bucket: "telegraf/default")
   |> range(start: -task.every)
   |> filter(fn: (r) =>
-    r._measurement == "mem" AND
+    r._measurement == "mem" and
     r.host == "myHost"
   )
 

content/v2.0/reference/flux/functions/built-in/outputs/to.md

@@ -12,8 +12,7 @@ weight: 401
 
 The `to()` function writes data to an **InfluxDB v2.0** bucket.
 
-_**Function type:** Output_  
-_**Output data type:** Object_
+_**Function type:** Output_
 
 ```js
 to(
@@ -39,6 +38,18 @@ to(
 )
 ```
 
+{{% note %}}
+### Output data requirements
+The `to()` function converts output data into line protocol and writes it to InfluxDB.
+Line protocol requires each record to have a timestamp, a measurement, a field, and a value.
+All output data must include the following columns:
+
+- `_time`
+- `_measurement`
+- `_field`
+- `_value`
+{{% /note %}}
+
 ## Parameters
 {{% note %}}
 `bucket` OR `bucketID` is **required**.