String.substitute

[Logan Smyth]

Template literals evaluate to simple strings, there is no way to pass a
reference to an un-evaluated template literal. The function method is the
only way. Programmatically

```
String.substitute({ year: 2015}, `Last year was ${year-1}`);
```

is identical to

```
var str = `Last year was ${year-1}`
String.substitute({ year: 2015}, str);
```

How would it ever know that it was supposed to skip evaluating the template
string first before calling the function?


On Wed, Aug 12, 2015 at 7:55 AM, Edwin Reynoso <eorroe at gmail.com> wrote:

> With `String.substitute()` you'd still be able to evaluate expressions,
> it's kind of like changing scope, or passing an object to use for scoped
> variables, which is not possible:
>
> ```JS
> substitute({ year: 2015 }, 'Last year was year ${year-1}'); // Will throw
> an error
> ```
>
> You can't evaluate with your function
>
> With `String.substitute()` you would be able to:
>
> ```JS
> String.substitute({ year: 2015}, `Last year was ${year-1}`);
> ```
>
> You also miss **New Lines** which is another thing template literals
> solved, so yes you could just add `\n` but that's the point of why template
> literals take care of that for you
>
> On Wed, Aug 12, 2015 at 10:49 AM, Elie Rotenberg <elie at rotenberg.io>
> wrote:
>
>> ```
>> function substitute(obj, str) {
>>   return str.replace(/\${([^}]*)}/g, (m, p) => obj[p]);
>> }
>>
>> substitute({ year: 2015 }, 'This is year ${year}'); // === 'This is year
>> 2015'
>> ```
>>
>>
>> On Wed, Aug 12, 2015 at 4:42 PM, Nathaniel Higgins <nat at nath.is> wrote:
>>
>>> Am I being naive or could this just be written in user space?
>>>
>>> Sent from my iPhone
>>>
>>> On 12 Aug 2015, at 15:31, Edwin Reynoso <eorroe at gmail.com> wrote:
>>>
>>> Yes of course, still requires 1.Destructuring, and making a function for
>>> each type of string to return. Defeats the purpose.
>>>
>>> I'd have to make different functions for each template:
>>>
>>> ```JS
>>> const yearTemplate = ({ year }) => `This year is ${year}`;
>>>
>>> const ageTemplate = ({ age}) => `I'm ${age} yrs old`;
>>> ```
>>>
>>> Compare to:
>>>
>>> ```JS
>>> let yearSentence = String.substitute({ year: 2015}, `This year is
>>> ${year}`);
>>> let ageSentence = String.substitute({ age:100 }, `I'm ${age} yrs old`);
>>> ```
>>>
>>> On Wed, Aug 12, 2015 at 10:19 AM, Claude Pache <claude.pache at gmail.com>
>>> wrote:
>>>
>>>>
>>>> > Le 12 août 2015 à 15:41, Edwin Reynoso <eorroe at gmail.com> a écrit :
>>>> >
>>>> > Could we make the following possible, I can't seem to think of a way
>>>> to do it, since template literals are evaluated with the current scope,
>>>> also tried with `eval` but shouldn't even use that at all:
>>>> >
>>>> > ```JS
>>>> > String.substitute( { year: 2015 }, `This year is ${year}` ); //
>>>> Returns "This year is 2015"
>>>> > ```
>>>> >
>>>> > Yes I'm aware I could do the following:
>>>> >
>>>> > ```JS
>>>> > var obj = { year:2015 }
>>>> >
>>>> > `This year is ${obj.year}`
>>>> > ```
>>>> >
>>>> > The point is to get rid of the part where I reference `obj` all the
>>>> time.
>>>> >
>>>> > I could just use destructuring:
>>>> >
>>>> > ```JS
>>>> > var { year } = { year: 2015 }
>>>> >
>>>> > `This year is ${year}`
>>>> > ```
>>>> >
>>>> > So yes destructuring takes care of most of this just fine, but the
>>>> point is to have a template literal evaluate as a pass reference and not
>>>> right away.
>>>> >
>>>> > You can't make your own function and pass in a template literal
>>>> that's not evaluated when passed as a reference, I'm not sure if anyone
>>>> will actually want this but me. Please let me know. Thanks
>>>>
>>>> There is a general trick for deferring evaluation (of a template
>>>> literal or of anything else): enclosing it in a function.
>>>>
>>>> ```js
>>>> const myTemplate = ({ year }) => `This year is ${year}`
>>>>
>>>> myTemplate({ year: 2015 })
>>>> ```
>>>>
>>>> —Claude
>>>>
>>>>
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>>
>
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