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Use if/else for boolean, range, or compound conditions; use switch to match one expression against discrete values; and use a dispatch table when a key-to-handler mapping makes the available actions clearer. None is universally best: choose the form that makes the decision easiest for your team to understand and maintain.
How should you choose?
| Pattern | Best fit | Watch for |
|---|---|---|
if/else |
Truthiness checks, ranges, or conditions combining multiple tests. | Long or deeply nested chains can obscure which condition wins. |
switch |
One expression matched against several discrete values. | Execution falls through after a match unless stopped with break or otherwise exited. |
| Dispatch table | A discrete key-to-handler mapping where representing the choices as data is clearer. | It is not a natural replacement for ranges or compound predicates; define behavior for unknown keys. |
When is if/else the clearest choice?
Use if/else when the decision is about whether a condition is true, how a value compares to a boundary, or whether several tests are satisfied together. JavaScript evaluates an if condition as truthy or falsy. In an else if chain, conditions are checked in order, and evaluation stops at the first true condition. That order is part of the behavior, so put more specific or higher-priority cases first when it matters.
if (score >= 90) {
grade = "A";
} else if (score >= 80) {
grade = "B";
} else {
grade = "C or below";
}For guard conditions, consecutive if statements with early returns can keep the main path uncluttered. This is a style option rather than a rule: use it when each condition independently ends or redirects the current operation.
function send(message) {
if (!message) return;
if (!isConnected()) return;
transmit(message);
}MDN recommends using block statements, particularly with nested if statements, to make control flow less confusing. MDN: if…else.
#1 Best Overall
When does switch fit better?
Choose switch when one expression can have a set of discrete values and each value leads to a branch. Cases are compared using strict equality, so values must match in both type and value. As MDN puts it, “The switch statement evaluates an expression, matching the expression’s value against a series of case clauses, and executes statements after the first case clause with a matching value, until a break statement is encountered.” MDN Web Docs, “switch – JavaScript”.
switch (status) {
case "ready":
start();
break;
case "paused":
pause();
break;
default:
reportUnknownStatus(status);
}Without a break, execution continues into the following case. Fall-through can be intentional when multiple cases share behavior, but accidental fall-through is a common bug. Include a default branch when an unrecognized value needs explicit handling; if no action is appropriate, make that choice clear in the code.
Rank #2
When is a dispatch table useful?
A dispatch table stores the relationship between keys and actions as data, commonly with an object or a Map. It can make a set of discrete choices easier to scan when the important structure is “this key selects this handler,” or when handlers need to be added, removed, or passed around independently of the selection logic.
const handlers = {
ready: start,
paused: pause
};
const handler = handlers[status];
if (handler) {
handler();
} else {
reportUnknownStatus(status);
}Think through unknown keys and object-key behavior explicitly. The example checks whether a handler was found before calling it; production code should also account for the expected input domain and the shape of its table. A dispatch table does not make range logic or compound conditions clearer merely by moving them into a lookup structure.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →With Map, keys are not restricted to strings and symbols as object property keys are. MDN says the specification requires Map implementations to provide access times that are, on average, sublinear in the collection size. That is not a guarantee that every lookup is O(1), nor evidence that a Map dispatch is faster than an object, switch, or if/else in a particular application. MDN: Map.
Is one pattern faster?
There is no comparative benchmark established here for these patterns. The claim that property access may outperform string comparisons is an intuition, not a measured result. If speed matters, benchmark representative inputs and handlers on the target runtime; measure the actual workload rather than assuming syntax determines performance.
Rank #4
What the original poll can—and cannot—tell you
The SitePoint Forums poll, posted September 10, 2018, asked readers which they preferred: “if/else,” “switch/case,” or “dispatch table.” The original poster described moving from if/else to switch and then favoring dispatch tables, while replies emphasized readability and what colleagues could maintain. One respondent preferred switch for more than two suitable discrete choices; another noted that dispatch tables are a poor fit for truthiness checks and ranges; a later reply favored early returns. These are individual opinions in a dated discussion, not a representative survey or a current consensus. SitePoint Forums discussion.
Quick Recap
A practical decision rule
- Use
if/elsefor truthy/falsy checks, ranges, and combined predicates. - Use
switchwhen one value is matched against several discrete alternatives and the branch structure reads naturally. - Use a dispatch table when a key-to-handler mapping is the clearest way to express the available actions.
- Follow the conventions of the people who will maintain the code, and make missing or unexpected inputs explicit.
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