toJsonString — GTM Variable Template for String

VARIABLES › STRING

toJsonString EXTENDED String

Direct (.tpl) Apply (.tpl) Add to GTM

Converts the input into a JSON string. If the value cannot be parsed, returns undefined.

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When to Use This

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Examples

Object to JSON▶ Try

INPUT

Input Value: {name: "John", age: 30}

OUTPUT

{"name":"John","age":30}

Array to JSON▶ Try

INPUT

Input Value: [1, 2, 3, "test"]

OUTPUT

[1,2,3,"test"]

String to JSON▶ Try

INPUT

Input Value: hello

OUTPUT

"hello"

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Live Sandbox

This is what you'll see when you open this variable in Google Tag Manager. Hover the icons for details.

toJsonString

Read-Only Try Live

Input Value

💾 The JavaScript object or value to convert to JSON.

Input Setup

Input Function (optional)

⚙️ Optional pre-processing function applied to the input before internal logic (e.g., clean object properties, add metadata). Internal transformations will still apply afterward.

Result Handling

Output Function (optional)

⚙️ Optional function to apply to the result before returning it (e.g., str => str.replace(/"/g, "'") for quote replacement, str => btoa(str) for base64 encoding). Useful for chaining transformations on the output.

Input Value object

💡 Type any text to see the result update live

🎯 Using special value — click input to type instead

Test with:

Falsy undefined null "" empty 0 false NaN

Truthy true 42 "hello" {} empty [] empty {a:1} [1,2,3]

🔗 Result Handling — Chain Variables

Chain apply-mode variables to the output. Each variable receives the result of the previous one.

toJsonString()

+ Chain another variable

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Related Variables

Same category: String

→ charAt → collapseWhitespace → concat → countWordsInString → endsWith → extract → extractFirstSegment → extractNumber → fromBase64 → indexOf → left → matchAll → matchRegex → normalizeEmail → normalizePhone → padEnd → padStart → parseJSON → replaceAll → replaceAllWithRegex → replaceFirst → right → safeSplit → search → slice → slugify → split → startsWith → stripAccents → stripHtml → substringAfter → substringBefore → test → toBase64 → toCamelCase → toKebabCase → toLocaleLowerCase → toLocaleUpperCase → toLowerCase → toNumber → toSnakeCase → toStartCase → toString → toStringRepresentation → toUpperCase → toUpperFirst → trim → trimEnd → trimStart → truncate

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Under the Hood

📜 View Implementation Code

/**
 * Converts a JavaScript object or value into a JSON string.
 *
 * @param {any} data.inp - The JavaScript object or value to be converted into a JSON string.
 * @param {Function|string} [data.out] - Optional output handler: function to transform result or string with format.
 *
 * Direct-mode specific parameters:
 * @param {Function} [data.pre] - Optional pre-processor function to transform inp before conversion.
 *
 * @returns {string|undefined} A JSON string representation of the input value. Returns undefined if the value cannot be parsed (e.g. the object has a cycle).
 *
 * @framework ggLowCodeGTMKit
 */

const JSON = require('JSON');

const toJsonString = function(input) {
    return JSON.stringify(input);
};

const safeFunction = fn => typeof fn === 'function' ? fn : x => x;
const out = safeFunction(data.out);

// ===============================================================================
// toJsonString - Direct mode
// ===============================================================================
const applyCast = (castFn, value) => safeFunction(castFn)(value);
const processedInput = applyCast(data.pre, data.inp);
return out(toJsonString(processedInput));
// ===============================================================================
// toJsonString() – Apply Mode
// ===============================================================================
/*
return function(value) {
   return out(toJsonString(value));
};
*/

🧪 View Test Scenarios (7 tests)

✅ '[example] Object to JSON'
✅ '[example] Array to JSON'
✅ '[example] String to JSON'
✅ Number value - converts to JSON string
✅ Nested object - converts complex structure to JSON string
✅ Object with function property - function is omitted from JSON
✅ Undefined as standalone value - returns undefined