File size: 5,035 Bytes
e706de2 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | /**
* Solution 17: Basic PromptTemplate
*
* Goal: Build a PromptTemplate that replaces {variable} placeholders
*/
import {PromptTemplate} from '../../../../src/index.js';
// Test cases
async function exercise() {
console.log('=== Exercise 17: Basic PromptTemplate ===\n');
// Test 1: Simple translation prompt
console.log('--- Test 1: Simple Translation ---');
const translatePrompt = new PromptTemplate({
template: "Translate to {language}: {text}",
});
const result1 = await translatePrompt.format({
language: "Spanish",
text: "Hello, world!"
})
console.log('Input: "Hello, world!" → Spanish');
console.log('Result:', result1); // result1
console.log();
// Test 2: Email template with multiple variables
console.log('--- Test 2: Email Template ---');
const emailPrompt = new PromptTemplate({
template: `Dear {name},\n\nThank you for {action}. Your {item} will arrive on {date}.\n\nBest,\n{sender}`
});
const result2 = await emailPrompt.format({
name: "Patric Gutersohn",
action: "your order",
item: "Mac Studio M3 Ultra",
date: "24.12.2026",
sender: "Apple Inc."
})
console.log('Result:', result2);
console.log();
// Test 3: Auto-detect variables
console.log('--- Test 3: Auto-Detect Variables ---');
const autoPrompt = new PromptTemplate({
template: "In {city}, I love to visit {activity}"
});
console.log('Detected variables:', autoPrompt.inputVariables);
const result3 = await autoPrompt.format({
city: "Paris",
activity: "museums"
})
console.log('Result:', result3);
console.log();
// Test 4: Partial variables (defaults)
console.log('--- Test 4: Partial Variables ---');
const partialPrompt = new PromptTemplate({
template: "You are a {role} assistant. User: {input}",
partialVariables: { role: "helpful" }
});
const result4 = await partialPrompt.format({ input: "What's the weather?" })
console.log('Result:', result4);
console.log();
// Test 5: Validation error
console.log('--- Test 5: Validation Error ---');
const strictPrompt = new PromptTemplate({
template: "Hello {name}, you are {age} years old",
inputVariables: ["name", "age"]
});
try {
await strictPrompt.format({ name: "Alice" })
console.log('ERROR: Should have thrown validation error!');
} catch (error) {
console.log('✓ Validation error caught:', error.message);
}
console.log();
// Test 6: Use as Runnable (invoke)
console.log('--- Test 6: Use as Runnable ---');
const runnablePrompt = PromptTemplate.fromTemplate("Search for {topic}")
const result6 = await runnablePrompt.invoke({
topic: "artificial intelligence"
})
console.log('Invoked result:', result6);
console.log();
// Test 7: Complex nested replacement
console.log('--- Test 7: Complex Template ---');
const docPrompt = PromptTemplate.fromTemplate(`
Function: {function}
Parameters: {params}
Returns: {returns}
Description: {description}
`);
const result7 = await docPrompt.format({
function: "calculateSum",
params: "a: number, b: number",
returns: "number",
description: "Adds two numbers together"
})
console.log('Result:', result7); // result7
console.log();
console.log('✓ Exercise 1 complete!');
}
// Run the exercise
exercise().catch(console.error);
/**
* Expected Output:
*
* --- Test 1: Simple Translation ---
* Input: "Hello, world!" → Spanish
* Result: Translate to Spanish: Hello, world!
*
* --- Test 2: Email Template ---
* Result: Dear Patric Gutersohn,
*
* Thank you for your order. Your Mac Studio M3 Ultra will arrive on 24.12.2026.
*
* Best,
* Apple Inc.
*
* --- Test 3: Auto-Detect Variables ---
* Detected variables: ['city', 'activity']
* Result: In Paris, I love to visit museums
*
* --- Test 4: Partial Variables ---
* Result: You are a helpful assistant. User: What's the weather?
*
* --- Test 5: Validation Error ---
* ✓ Validation error caught: Missing required input variables: age
*
* --- Test 6: Use as Runnable ---
* Invoked result: Search for artificial intelligence
*
* --- Test 7: Complex Template ---
* Result:
* Function: calculateSum
* Parameters: a: number, b: number
* Returns: number
* Description: Adds two numbers together
*
* Learning Points:
* 1. PromptTemplate replaces {variable} placeholders
* 2. Auto-detection extracts variables from template
* 3. Partial variables provide defaults
* 4. Validation ensures all variables are provided
* 5. As a Runnable, prompts work with invoke()
* 6. Regex is key: /\{(\w+)\}/g finds all variables
*/ |