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Overview

The containsTarget function checks whether any stored rule targets inside the trie match the provided text. This is useful to verify if a specific replacement target exists anywhere in the trie.

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Function signature

containsTarget(trie: TrieNode, text: string, options?: { caseInsensitive?: boolean }): boolean

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Parameters

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trie
TrieNode
required
The trie whose nodes will be inspected. This trie should be constructed using the buildTrie function.
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text
string
required
The target text to locate. The function searches for this string among all target values stored in the trie.
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options
object
Optional matching controls:

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Returns

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result
boolean
True if a matching target is found, otherwise false. The function searches all nodes in the trie and returns true as soon as a match is found.

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Example usage

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Basic usage

import { buildTrie, containsTarget } from 'trie-rules';

const rules = [
  {
    from: ['example', 'sample'],
    to: 'demo',
  },
  {
    from: ['test'],
    to: 'verified',
  },
];

const trie = buildTrie(rules);

// Check if targets exist in the trie
console.log(containsTarget(trie, 'demo'));
// Output: true

console.log(containsTarget(trie, 'verified'));
// Output: true

console.log(containsTarget(trie, 'notfound'));
// Output: false

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Case-insensitive matching

import { buildTrie, containsTarget } from 'trie-rules';

const rules = [
  {
    from: ['example'],
    to: 'Demo',
  },
];

const trie = buildTrie(rules);

// Case-sensitive search (default)
console.log(containsTarget(trie, 'demo'));
// Output: false

console.log(containsTarget(trie, 'Demo'));
// Output: true

// Case-insensitive search
console.log(containsTarget(trie, 'demo', { caseInsensitive: true }));
// Output: true

console.log(containsTarget(trie, 'DEMO', { caseInsensitive: true }));
// Output: true

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Verifying unique targets

import { buildTrie, containsTarget } from 'trie-rules';

const rules = [
  {
    from: ['Sufyan', 'Sufyaan'],
    to: 'Sufyān',
  },
  {
    from: ['Ali', 'Alee'],
    to: 'ʿAlī',
  },
];

const trie = buildTrie(rules);

// Check which targets are present
const targets = ['Sufyān', 'ʿAlī', 'Umar'];
const presentTargets = targets.filter(target => 
  containsTarget(trie, target)
);

console.log(presentTargets);
// Output: ['Sufyān', 'ʿAlī']

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Checking for conflicts

import { buildTrie, containsTarget } from 'trie-rules';

const rules = [
  {
    from: ['example'],
    to: 'demo',
  },
];

const trie = buildTrie(rules);

// Before adding a new rule, check if the target already exists
const newTarget = 'demo';
if (containsTarget(trie, newTarget)) {
  console.log(`Target "${newTarget}" already exists in the trie`);
}

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Implementation details

The function uses a depth-first search algorithm:
  1. Initialize a stack with the root trie node
  2. While the stack is not empty:
    • Pop the current node
    • If the node has a target property, compare it with the search text
    • If a match is found, return true immediately
    • Push all child nodes onto the stack
  3. If no match is found after traversing all nodes, return false
The function skips special properties (isEndOfWord, target, options) and only traverses actual character nodes.

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Runtime complexity

The complexity is O(n) in the worst case, where:
  • n = total number of nodes in the trie
The function may need to visit every node in the trie to find a target or determine that it doesn’t exist. However, the search terminates early when a match is found.

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Use cases

  • Validation: Verify that expected targets were added to the trie
  • Conflict detection: Check if a target already exists before adding new rules
  • Testing: Confirm rule targets in unit tests
  • Debugging: Locate which targets are present when troubleshooting
  • Rule analysis: Identify duplicate or overlapping targets
  • buildTrie - Constructs the trie that this function searches
  • containsSource - Checks if a source string exists in the trie
  • optimizeRules - Can detect target conflicts during optimization

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