How to get the field value when clicking on a button on a Slack app?

Question

I've studying Slack Bolt Framework and I created a very simple app that works with a slash command. When I type '/cep' the following screen appears:

printscreen

How can I get the input value field when I click the button?

I'm usind Bolt Framework with Javascript.

Here the screen code:

/ Listen for a slash command invocation 'Busca de CEP'
app.command('/cep', async ({ command, ack, say }) => {
  
  // Acknowledge the command request
  await ack();
  
  await say(
    {
        "blocks": [
            {
                "type": "header",
                "text": {
                    "type": "plain_text",
                    "text": "🔍 Busca de Endereço",
                    "emoji": true
                }
            },
            {
                "type": "divider"
            },
            {
                "type": "section",
                "text": {
                    "type": "plain_text",
                    "text": "Digite o CEP que deseja pesquisar:",
                    "emoji": true
                }
            },
            {
                "type": "input",
                "element": {
                    "type": "plain_text_input",
                    "action_id": "plain_text_input-action"
                },
                "label": {
                    "type": "plain_text",
                    "text": " ",
                    "emoji": true
                }
            },
            {
                "type": "actions",
                "elements": [
                    {
                        "type": "button",
                        "text": {
                            "type": "plain_text",
                            "text": "Buscar",
                            "emoji": true
                        },
                        "value": "submitCEPButton",
                        "action_id": "submitCEPButton"
                    }
                ]
            }
        ]
    }
  )
  
});

Here the slash command code:

/ Action listener function called when an interactive component with action_id of “click_me_button” is triggered
app.action('submitCEPButton', async ({ ack, body, client, say }) => {
  // Acknowledge action request before anything else
  await ack();
  
  let channelID = body.channel.id
  let userID = body.user.id
  
  // Respond to action with an ephemeral message
  await client.chat.postEphemeral({
    channel: channelID,
    user: userID,
    text: `<@${userID}> clicked the button! 🎉`
  });
});

UPDATE

Screen code when I type the slash command '/cep'

app.command('/cep', async ({ command, ack, say }) => {
  
  // Acknowledge the command request
  await ack();
  
  await say(
    {
        "blocks": [
            {
                "type": "header",
                "block_id": "headerBlock",
                "text": {
                    "type": "plain_text",
                    "text": "🔍 Busca de Endereço",
                    "emoji": true
                }
            },
            {
                "type": "divider",
                "block_id": "dividerBlock",
            },
            {
                "type": "section",
                "block_id": "sectionBlock",
                "text": {
                    "type": "plain_text",
                    "text": "Digite o CEP que deseja pesquisar:",
                    "emoji": true
                }
            },
            {
                "type": "input",
                "block_id": "inputBlock",
                "element": {
                    "type": "plain_text_input",
                    "action_id": "inputCEP"
                },
                "label": {
                    "type": "plain_text",
                    "text": " ",
                    "emoji": false
                }
            },
            {
                "type": "actions",
                "block_id": "submitBlock",
                "elements": [
                    {
                        "type": "button",
                        "text": {
                            "type": "plain_text",
                            "text": "Buscar",
                            "emoji": true
                        },
                        "value": "submitCEPButton",
                        "action_id": "submitCEPButton"
                    }
                ]
            }
        ]
    }
  )
  
});

The command when I click the button

// Action listener function called when an interactive component with action_id of “click_me_button” is triggered
app.action('submitCEPButton', async ({ ack, body, client, say }) => {
  // Acknowledge action request before anything else
  await ack();
  
  let channelID = body.channel.id
  let userID = body.user.id
  console.log(body.state.values)
});

The result printed in console:

{
  njQfY: {
    'plain_text_input-action': { type: 'plain_text_input', value: 'abc123' }
  }
}

Answer 1

you need to view.state.values from the view_submission payload.

Refrence : https://api.slack.com/reference/interaction-payloads/views

You need to focus on block_id & action_id as that can be tricky.