EndImpressionRegion

→ undefined

Bare-name Core form of Platform.Function.EndImpressionRegion — marks the end of an impression region. Bare alias returns undefined (Platform.Function form returns null).

Runtime verified Differs from official docs Test scripts included

Syntax

EndImpressionRegion([closeAll])

0–1 arguments

Parameters

Name	Type	Required	Description
closeAll	string | boolean | number	No	When true, closes every nested impression region still open.

Show test script

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Chapter: Parameters — EndImpressionRegion([closeAll])
 *
 * Proves:
 *   1. After Platform.Load("core", "1.1.5") the bare name is a function
 *      (the documented requires_core_load contract).
 *   2. The documented 0-argument form is callable and does NOT throw —
 *      unlike its paired BeginImpressionRegion half.
 *   3. The optional closeAll parameter accepts a boolean in either state
 *      (true and false) without throwing.
 *   4. Type-acceptance matrix for closeAll: a string and a number are
 *      also accepted (coerced) without throwing — same meaningful
 *      call-level outcome as the boolean path.
 *   5. CONTRAST with Platform.Function: null in the closeAll position is
 *      ACCEPTED by the bare alias (does not throw) — the qualified form
 *      throws the security-descriptor error for the same input.
 *   6. CONTRAST with Platform.Function: arity 2 is ACCEPTED by the bare
 *      alias (does not throw) — the qualified form throws for arity 2/3.
 *   7. Every successful bare-alias call returns undefined (contrast with
 *      the Platform.Function form's null is covered in returns-undefined).
 *
 * SCOPE: CloudPage GET only. Nothing below asserts how the call behaves
 * inside an actual email send.
 *
 * NOT ASSERTED: whether closeAll really closes every nested region, or
 * whether an impression is recorded in tracking.
 *
 * EXPECTED OUTPUT: every line starts with PASS. A FAIL means the runtime no
 * longer matches the documented claim and the page must be revised.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}
function assertThrows(id, fn) {
    var threw = false, msg = "";
    try { fn(); } catch (ex) { threw = true; msg = ex.message; }
    Platform.Response.Write((threw ? "PASS " : "FAIL ") + id + " -> " + (threw ? "threw: " + msg : "did NOT throw") + "\n");
}
function assertNoThrow(id, fn) {
    var threw = false, msg = "";
    try { fn(); } catch (ex) { threw = true; msg = ex.message; }
    Platform.Response.Write((threw ? "FAIL " : "PASS ") + id + " -> " + (threw ? "threw: " + msg : "did not throw") + "\n");
}
function typeOf(fn) {
    try { return "" + fn(); } catch (ex) { return "THREW: " + ("" + ex.message); }
}

/* 1. The bare name resolves as a function after the Core load. */
assert("typeof EndImpressionRegion is function after Platform.Load", typeOf(function () { return typeof EndImpressionRegion; }), "function");

/* 2. The 0-argument form is callable. */
assertNoThrow("arity 0 does not throw", function () {
    return EndImpressionRegion();
});
var r0 = EndImpressionRegion();
assert("arity 0 returns typeof undefined", typeOf(function () { return typeof r0; }), "undefined");
assert("arity 0 returns === undefined", r0 === undefined ? "true" : "false", "true");

/* 3. closeAll accepts a boolean in either state. */
assertNoThrow("closeAll = true does not throw", function () {
    return EndImpressionRegion(true);
});
var rTrue = EndImpressionRegion(true);
assert("closeAll = true returns typeof undefined", typeOf(function () { return typeof rTrue; }), "undefined");
assertNoThrow("closeAll = false does not throw", function () {
    return EndImpressionRegion(false);
});
var rFalse = EndImpressionRegion(false);
assert("closeAll = false returns typeof undefined", typeOf(function () { return typeof rFalse; }), "undefined");

/* 4. Type-acceptance — string and number counterparts are Accepted. */
assertNoThrow("closeAll = \"true\" (string) is accepted", function () {
    return EndImpressionRegion("true");
});
var rStr = EndImpressionRegion("true");
assert("closeAll = \"true\" returns typeof undefined", typeOf(function () { return typeof rStr; }), "undefined");
assertNoThrow("closeAll = 1 (number) is accepted", function () {
    return EndImpressionRegion(1);
});
var rNum = EndImpressionRegion(1);
assert("closeAll = 1 returns typeof undefined", typeOf(function () { return typeof rNum; }), "undefined");
assertNoThrow("closeAll = 0 (number) is accepted", function () {
    return EndImpressionRegion(0);
});
assertNoThrow("closeAll = \"false\" (string) is accepted", function () {
    return EndImpressionRegion("false");
});

/* 5. CONTRAST — bare alias accepts null; Platform.Function rejects it. */
assertNoThrow("closeAll = null does not throw on bare alias (Platform.Function throws)", function () {
    return EndImpressionRegion(null);
});
var rNull = EndImpressionRegion(null);
assert("closeAll = null returns typeof undefined", typeOf(function () { return typeof rNull; }), "undefined");

/* 6. CONTRAST — bare alias accepts arity 2; Platform.Function rejects it. */
assertNoThrow("arity 2 does not throw on bare alias (Platform.Function throws)", function () {
    return EndImpressionRegion(true, true);
});
var r2 = EndImpressionRegion(true, true);
assert("arity 2 returns typeof undefined", typeOf(function () { return typeof r2; }), "undefined");
</script>

Description

EndImpressionRegion() is the bare-name Core-library form of Platform.Function.EndImpressionRegion(). It requires Platform.Load("core", "1.1.5") before use — the bare name is undefined until the load has run.

Once loaded, the bare name IS defined as a function and can be called without throwing. Because BeginImpressionRegion is unusable from SSJS, this method has no practical effect in SSJS either — impression regions are an AMPscript-only feature.

Show test script

<script runat="server">
/*
 * Chapter: Description — bare-name Core form, Platform.Load required,
 * callable without throwing, no practical SSJS effect.
 *
 * Proves:
 *   1. Platform.Load("core", "1.1.5") is REQUIRED: the bare name is
 *      undefined before the load and a function after it. The pre-load
 *      typeof is resolved inside a thunk so an unbound global cannot abort
 *      the page.
 *   2. Once loaded the bare name IS defined as a function and can be
 *      called without throwing (0-arg and closeAll=true forms).
 *   3. Control: BeginImpressionRegion remains unusable from SSJS — the
 *      paired half throws — so this End method has no practical effect
 *      in SSJS either; impression regions are an AMPscript-only feature.
 *   4. The AMPscript close form via TreatAsContent does not throw and
 *      produces no output (workaround for pairing with an AMPscript open).
 *
 * SCOPE: CloudPage GET only — the email/send context is not covered by any
 * assertion here.
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}
function assertThrows(id, fn) {
    var threw = false, msg = "";
    try { fn(); } catch (ex) { threw = true; msg = ex.message; }
    Platform.Response.Write((threw ? "PASS " : "FAIL ") + id + " -> " + (threw ? "threw: " + msg : "did NOT throw") + "\n");
}
function assertNoThrow(id, fn) {
    var threw = false, msg = "";
    try { fn(); } catch (ex) { threw = true; msg = ex.message; }
    Platform.Response.Write((threw ? "FAIL " : "PASS ") + id + " -> " + (threw ? "threw: " + msg : "did not throw") + "\n");
}
function typeOf(fn) {
    try { return "" + fn(); } catch (ex) { return "THREW: " + ("" + ex.message); }
}

/* 1. Platform.Load is required — check BEFORE loading. */
assert("bare EndImpressionRegion is undefined before Platform.Load", typeOf(function () { return typeof EndImpressionRegion; }), "undefined");

Platform.Load("core", "1.1.5");

assert("bare EndImpressionRegion is a function after Platform.Load", typeOf(function () { return typeof EndImpressionRegion; }), "function");

/* 2. Once loaded it can be called without throwing. */
assertNoThrow("bare EndImpressionRegion() does not throw", function () {
    return EndImpressionRegion();
});
assertNoThrow("bare EndImpressionRegion(true) does not throw", function () {
    return EndImpressionRegion(true);
});

/* 3. Control — Begin is unusable, so End has no practical SSJS effect. */
assertThrows("control: bare BeginImpressionRegion throws (AMPscript-only feature)", function () {
    return BeginImpressionRegion("control-region");
});
assertThrows("control: Platform.Function.BeginImpressionRegion throws identically", function () {
    return Platform.Function.BeginImpressionRegion("control-region");
});

/* 4. AMPscript close via TreatAsContent works as the pairing workaround. */
assertNoThrow("workaround TreatAsContent end does not throw", function () {
    return Platform.Function.TreatAsContent('%%[EndImpressionRegion()]%%');
});
var tac = Platform.Function.TreatAsContent('%%[EndImpressionRegion()]%%');
assert("workaround TreatAsContent end has no output", "" + tac, "");
assert("typeof the TreatAsContent result is string", typeOf(function () { return typeof tac; }), "string");
</script>

Return value

The bare alias returns undefined (typeof "undefined"). This differs from its Platform.Function.EndImpressionRegion counterpart, which returns a genuine null (typeof "object", === null). The official docs type the return as void.

Differs from official Salesforce docs

The official docs type the return as void. The bare-name Core alias returns undefined (typeof “undefined”), whereas the Platform.Function form returns a genuine null (typeof “object”, === null).

Show test script — bare alias returns undefined, not void

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Differs-from-docs claim: the official Salesforce documentation types the
 * return of EndImpressionRegion as VOID. At runtime the bare-name Core
 * alias returns undefined (typeof "undefined"), whereas the qualified
 * Platform.Function form returns a genuine null (typeof "object", === null).
 *
 * Official docs: EndImpressionRegion([closeAll]) returns void
 * SFMC runtime:  bare alias → undefined; Platform.Function → null
 *
 * Proves every part of the callout:
 *   1. DEV the bare-alias 0-arg return is typeof "undefined" (docs: void —
 *      which would also surface as undefined in JS, but the page documents
 *      the concrete undefined vs the Platform.Function null contrast).
 *   2. DEV the bare-alias return is strictly === undefined.
 *   3. DEV the bare-alias return is NOT === null — distinguishing it from
 *      the Platform.Function form.
 *   4. DEV the closeAll form of the bare alias also returns undefined.
 *   5. CONTRAST: Platform.Function.EndImpressionRegion() returns typeof
 *      "object", === null, and is NOT === undefined — so the two forms
 *      disagree with each other (and both disagree with a pure void story
 *      once the Platform.Function null is considered).
 *
 * SCOPE: all of the above was observed on a plain CloudPage GET. No
 * assertion here speaks to what happens during a real email send.
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}
function typeOf(fn) {
    try { return "" + fn(); } catch (ex) { return "THREW: " + ("" + ex.message); }
}

/* 1-3. DEV the bare-alias 0-arg call returns undefined, not null. */
var b = EndImpressionRegion();
assert("DEV bare-alias returns typeof undefined (docs: void)", typeOf(function () { return typeof b; }), "undefined");
assert("DEV bare-alias returns === undefined (docs: void)", b === undefined ? "true" : "false", "true");
assert("DEV bare-alias is NOT === null (contrast Platform.Function)", b === null ? "true" : "false", "false");

/* 4. The closeAll form of the bare alias returns undefined too. */
var bc = EndImpressionRegion(true);
assert("DEV bare closeAll form returns typeof undefined", typeOf(function () { return typeof bc; }), "undefined");
assert("DEV bare closeAll form returns === undefined", bc === undefined ? "true" : "false", "true");
assert("DEV bare closeAll form is NOT === null", bc === null ? "true" : "false", "false");

/* 5. CONTRAST — the Platform.Function form returns a genuine null. */
var p = Platform.Function.EndImpressionRegion();
assert("DEV Platform.Function form returns typeof object (docs: void)", typeOf(function () { return typeof p; }), "object");
assert("DEV Platform.Function form returns === null (docs: void)", p === null ? "true" : "false", "true");
assert("DEV Platform.Function form is NOT === undefined", p === undefined ? "true" : "false", "false");
var pc = Platform.Function.EndImpressionRegion(true);
assert("DEV Platform.Function closeAll returns === null", pc === null ? "true" : "false", "true");
</script>

Example

Platform.Load("core", "1.1.5");
EndImpressionRegion(); // returns undefined (Platform.Function form returns null)

Show test script

<script runat="server">
Platform.Load("core", "1.1.5");

/*
 * Chapter: Example
 *
 * Proves the page example line by line:
 *   1. The example's Platform.Load("core", "1.1.5") is what makes the bare
 *      name resolvable — typeof is "function" afterwards.
 *   2. The example call EndImpressionRegion() returns undefined, matching
 *      the example's own comment.
 *   3. DEV contrast asserted by the comment: the Platform.Function form
 *      returns null for the same call shape (docs type both as void).
 *
 * SCOPE: CloudPage GET only — no email/send-context behaviour is asserted.
 *
 * NOT ASSERTED: whether an impression is actually recorded in tracking.
 *
 * EXPECTED OUTPUT: every line starts with PASS.
 */

function assert(id, actual, expected) {
    Platform.Response.Write((actual === expected ? "PASS " : "FAIL ") + id + " -> [" + actual + "]\n");
}
function typeOf(fn) {
    try { return "" + fn(); } catch (ex) { return "THREW: " + ("" + ex.message); }
}

/* 1. The Core load from the example makes the bare name usable. */
assert("the example's Core load made the bare name a function", typeOf(function () { return typeof EndImpressionRegion; }), "function");

/* 2. The example call returns undefined. */
var r = EndImpressionRegion();
assert("example EndImpressionRegion() returns typeof undefined", typeOf(function () { return typeof r; }), "undefined");
assert("example EndImpressionRegion() returns === undefined", r === undefined ? "true" : "false", "true");
assert("example EndImpressionRegion() is NOT === null", r === null ? "true" : "false", "false");

/* 3. DEV the comment's contrast with Platform.Function is accurate. */
var p = Platform.Function.EndImpressionRegion();
assert("DEV contrast: Platform.Function form returns === null", p === null ? "true" : "false", "true");
assert("DEV contrast: Platform.Function form returns typeof object", typeOf(function () { return typeof p; }), "object");
</script>

See Also

See Also

• Platform.Function.EndImpressionRegion — qualified form (no Platform.Load required)
• BeginImpressionRegion