template.arrayToString.json

{
    "$schema": "http://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "args": {
            "type": "array"
        },
        "delimiter": {
            "type": "string",
            "defaultValue": " "
        },
        "contentRoot": {
            "type": "string"
        },
        "templateId" :{
            "defaultValue": "",
            "type": "string"
        }
    },
    "variables": {
        "ids": [
            "[concat('ArrayToString', uniqueString(string(parameters('args'))))]",
            "[parameters('templateId')]"
        ],
        "id" :"[variables('ids')[length(take(parameters('templateId'),1))]]"
    },
    "resources": [
        {
            "type": "Microsoft.Resources/deployments",
            "name": "[concat(variables('id'), '0')]",
            "apiVersion": "2015-01-01",
            "properties": {
                "templateLink": {
                    "contentVersion": "1.0.0.0",
                    "uri": "[concat(parameters('contentRoot'), '/template.stringJoin.json')]"
                },
                "mode": "Incremental",
                "parameters": {
                    "stringA": {
                        "value": ""
                    },
                    "delimiter": {
                        "value": ""
                    },
                    "stringB": {
                        "value": ""
                    }
                }
            }
        },
        {
            "type": "Microsoft.Resources/deployments",
            "name": "[concat(variables('id'), add(copyindex(),1))]",
            "apiVersion": "2015-01-01",
            "copy": {
                "name": "arrayJoinLoop",
                "count": "[length(parameters('args'))]"
            },
            "properties": {
                "templateLink": {
                    "contentVersion": "1.0.0.0",
                    "uri": "[concat(parameters('contentRoot'), '/template.stringJoin.json')]"
                },
                "mode": "Incremental",
                "parameters": {
                    "stringA": {
                        "value": "[reference(concat(variables('id'), copyindex())).outputs.result.value]"
                    },
                    "delimiter": {
                        "value": "[parameters('delimiter')]"
                    },
                    "stringB": {
                        "value": "[parameters('args')[copyindex()]]"
                    }
                }
            },
            "dependsOn": [
                "[concat(variables('id'), copyindex())]"
            ]
        }
    ],
    "outputs": {
        "Result": {
            "type": "string",
            "value": "[reference(concat(variables('id'), length(parameters('args')))).outputs.result.value]"
        }
    }
}