#1994 Add Cohere as a Chat Completion source

src/prompt-converters.js

@@ -1,3 +1,5 @@
+require('./polyfill.js');
+
 /**
  * Convert a prompt from the ChatML objects to the format used by Claude.
  * @param {object[]} messages Array of messages
@@ -188,6 +190,64 @@ function convertClaudeMessages(messages, prefillString, useSysPrompt, humanMsgFi
     return { messages: mergedMessages, systemPrompt: systemPrompt.trim() };
 }
 
+/**
+ * Convert a prompt from the ChatML objects to the format used by Cohere.
+ * @param {object[]} messages Array of messages
+ * @param {string}   charName Character name
+ * @param {string}   userName User name
+ * @returns {{systemPrompt: string, chatHistory: object[], userPrompt: string}} Prompt for Cohere
+ */
+function convertCohereMessages(messages, charName = '', userName = '') {
+    const roleMap = {
+        'system': 'SYSTEM',
+        'user': 'USER',
+        'assistant': 'CHATBOT',
+    };
+    const placeholder = '[Start a new chat]';
+    let systemPrompt = '';
+
+    // Collect all the system messages up until the first instance of a non-system message, and then remove them from the messages array.
+    let i;
+    for (i = 0; i < messages.length; i++) {
+        if (messages[i].role !== 'system') {
+            break;
+        }
+        // Append example names if not already done by the frontend (e.g. for group chats).
+        if (userName && messages[i].name === 'example_user') {
+            if (!messages[i].content.startsWith(`${userName}: `)) {
+                messages[i].content = `${userName}: ${messages[i].content}`;
+            }
+        }
+        if (charName && messages[i].name === 'example_assistant') {
+            if (!messages[i].content.startsWith(`${charName}: `)) {
+                messages[i].content = `${charName}: ${messages[i].content}`;
+            }
+        }
+        systemPrompt += `${messages[i].content}\n\n`;
+    }
+
+    messages.splice(0, i);
+
+    if (messages.length === 0) {
+        messages.unshift({
+            role: 'user',
+            content: placeholder,
+        });
+    }
+
+    const lastNonSystemMessageIndex = messages.findLastIndex(msg => msg.role === 'user' || msg.role === 'assistant');
+    const userPrompt = messages.slice(lastNonSystemMessageIndex).map(msg => msg.content).join('\n\n') || placeholder;
+
+    const chatHistory = messages.slice(0, lastNonSystemMessageIndex).map(msg => {
+        return {
+            role: roleMap[msg.role] || 'USER',
+            message: msg.content,
+        };
+    });
+
+    return { systemPrompt: systemPrompt.trim(), chatHistory, userPrompt };
+}
+
 /**
  * Convert a prompt from the ChatML objects to the format used by Google MakerSuite models.
  * @param {object[]} messages Array of messages
@@ -300,4 +360,5 @@ module.exports = {
     convertClaudeMessages,
     convertGooglePrompt,
     convertTextCompletionPrompt,
+    convertCohereMessages,
 };